A well-documented hyperurbanism is the substitution of the subjective for the objective case of pronouns in syndetic compounds (with and, or). Here are two examples from media language (emphasis added):

(1) “I’m picking you and I.” (John Feinstein, NPR, “Morning Edition,” May 24, 1993);

(2)  “Mozart wrote the Concerto for he and his sister.” (Bill Winans, WMHT-FM, November 19, 2010)

This grammatical solecism is often heard in British speech as well as American. Even as superlative a writer as P. D. James allows it:

(3) “And those two deaths bound you and she together indissolubly for life.” (P. D. James, Shroud for a    Nightingale [New York: Popular Library, 1971], p. 278)

While this mistake can easily be reckoned to result from a fear of the objective case in compounds involving one or more pronouns, a deeper analysis would take into account the creation of a spurious boundary separating the compound from the preposition. The speaker/writer who countenances this hyperurbanism implicitly erects a boundary on both sides of the compound, as if the latter were a binomial––a single unit––rather than two units joined by a conjunction, hence immune to case government and therefore in the uninflected (direct, non-oblique) subjective case.