During the past eighty years or so the conjunction “and/or” has regularly been used in pleadings, agreements, notices and other legal documents, both in South Africa and elsewhere.
Even though it has over the years, in several jurisdictions, been the subject of judicial disapproval, it has become increasingly common in legal writing.
As long ago as 1932, in Cochrane v Florida East Coast Ry Co 145 So 217 (1932) Terrell J said (at 218):
It is one of those inexcusable barbarisms which was sired by indolence and dammed by indifference… .
In the Supreme Court of Wisconsin, Fowler J, in Employers’ Mutual Liability Insurance Co of Wisconsin et al v Tollefsen et al Wis 263 N.W. 376 at 377 (1935), referred to “and/or” as “that thing”. This is what the judge said:
It is manifest that we are confronted with the task of first construing ‘and/or,’ that befuddling, nameless thing, that Janus-faced verbal monstrosity, neither word nor phrase, the child of a brain of some one too lazy or too dull to express his precise meaning, or too dull to know what he did mean, now commonly used by lawyers in drafting legal documents, through carelessness or ignorance or as a cunning device to conceal rather than express meaning with view to furthering the interest of their clients. We have even observed the ‘thing’ in statutes, in the opinions of courts, and in statements in briefs of counsel, some learned and some not.
In American General Insurance Co v Webster et al 118 SW 2d 1082 (1938 Tex App) Combs J said that “the abominable invention, ‘and/or” is as devoid of meaning as it is incapable of classification by the rules of grammar and syntax”.
In the Chancery Division in 1942, in Re Lewis, Goronwy v Richards  2 All ER 364 at 365 the court had to construct a will, leaving a bequest to “Margaret Ann and/or John Richards”. With reference to “and/or”, Farwell J said:
It is an unfortunate expression which I have not met before and which, I hope, I may never meet again.
In Raine v Drasin, 621 SW 2d 895 (Ky 1981) Lukowsky J, in a dissenting opinion in the Supreme Court of Kentucky, referred to “and/or” as “the much condemned conjunctive-disjunctive crutch of sloppy thinkers”.
In 1944, in the House of Lords, Viscount Simon LC in Bonitto v Fuerst Bros and Co Ltd  1 All ER 91 at 92, when dealing with the pleadings before the court, expressed himself as follows:
Para 18 stated the alternative claim in a variety of separated phrases, separated from one another by the repeated use of the bastard conjunction ‘and/or’ which has, I fear, become the Commercial Court’s contribution to Basic English.
In Australia Williams J described an expression in which “and/or” was used as “an elliptical and embarrassing expression which endangers accuracy for the sake of brevity” (Fadden v Deputy Federal Commissioner of F Taxation, (1943) 68 C. L. R. 76). In Millen v Grove  VLR 259 at 260 Duffy J said that the draftsman (of a notice to a tenant to quit) “invited trouble by the common and deplorable affection for the form ‘and/or’”.
Also in South Africa the expression “and/or” and its Afrikaans equivalent, “en/of”, have been subjected to judicial scrutiny.
Ex Parte McDuling 1944 OPD 187 concerned the construction, in a will, of the phrase “death before age of 25 years and/or without lawful descendants”. Van den Heever J is reported (at 189) to have said the following:
Hierdie vertolking rym ook met die oorweging dat die lompe uitdrukking ‘en/of’ nie Afrikaans is nie; blykbaar het die opsteller van ons oorkonde hier ex majore cautela maar gedagteloos daardie Engelse ongerymdheid ‘and/or’ nageaap.
Dit is ‘n greep om helder begrippe te ontwyk, nie om hulle uit te druk nie; mens kan net sowel sê: ‘trousers is and/or are’.
In Saffer Clothing Industries (Pty) Ltd v Worcester Textiles (Pty) Ltd 1965 (2) SA 424 (C) the court struck out a phrase including such words from a declaration amplified by further particulars.
Some legal writers are of the view that “and/or” is not ambiguous at all. It has a definite meaning: when used properly the construct means “A or B or both”. It derives its criticism mainly from the inability of people to use it correctly. Despite certain contexts in which “and/or” should be avoided, the construct should not be discarded simply because individuals occasionally misuse the term. See Ira P Robbins: ‘And/or’ and the Proper Use of Legal Language Maryland Law Review, Forthcoming American University WCL Research Paper No 2017-10 (Date Written: March 6, 2017).
There are several South African judgments where our courts interpreted and gave meaning to the words “and/or”. These courts, in broad terms, applied the ordinary rules of interpretation, went out from the premise that the phrase has to be construed so as not to treat either the “and” or the “or” as pro non scripto and that it should be read disjunctively as well as conjunctively. Such judgments include Rex v Standard Tea and Coffee Co (Pty) Ltd and another 1951 (4) SA 412 (A) 415 - 416; Berman v Teiman 1975 (1) SA 756 (W) 757 - 758; Du Toit en ‘n ander v Barclays Nasionale Bank Bpk 1985 (1) SA 563 (A) 570 - 571; and Brink v Premier, Free State and another 2009 (4) SA 420 (SCA) 424 - 425. See also Thomas v BMW South Africa (Pty) Ltd 1996 (2) SA 106 (C) 117 - 118.
The use of a single “and/or” in a paragraph or sentence will not necessarily give rise to ambiguity. The potential for uncertainty will, however, be compounded where the drafter uses a string of “and/or”s. The addition of each further “and/or” exponentially increases the possible permutations or meanings. In R v Adams and others 1959 (1) SA 646 (SCC) 657 - 658 the defence complained about the extravagant use of the conjunction “and/or”. It was suggested that if all the “and/or”s are added together, there will, under three paragraphs of part of the main charge, be no less than 498,015 combinations.
Despite judicial disapproval over a long period of time, the phrase “and/or” has become embedded in legal writing. It is unlikely that it will be discarded. It is here to stay.