At Berkeley (Frederick Wiseman, 2013)
teacher: i don't know, CAN you?
student: yes, also colloquial irregularities occur frequently in any language and since you and the rest of our present company understood my intended meaning, being particular about the distinctions between "can" and "may" is purely pedantic and arguably pretentious
Cuno Amiet (Swiss, 1868-1961), Jungfrau, 1943. Watercolour and pencil, 15.5 x 20.5 cm.