Last year (I think), a friend fulminated on Facebook that an ABC newsreader had said something like “The robbers took money off the people”. She asked rhetorically “Where’s your grammar?”. I replied that there’s nothing grammatically wrong with saying off instead of from; it’s a matter of semantics (meaning) or usage.
The father of another friend died recently. The funeral was livestreamed, which I missed, but it’s still available to watch. My friend said that his father was insistent on grammar. Asking “Can I have a glass of wine?” would be answered by “I think you mean ‘May I have a glass of wine?’”. Again, there’s nothing grammatically wrong with Can I have.
Google Ngrams shows that take money from people is used far more commonly than take money off people (for all inflections of take), so my first friend may be worrying unnecessarily. In any case, her time might have been better spent sending an email to the ABC than posting on Facebook. On the other hand Can I have and May I have have a mixed history. According to Google Ngrams, Can I have was more common until about 1900-1910, at which point it lost favour to May I have. The latter reached its peak about 1940-1950, then suddenly lost favour again, and was overtaken by Can I have about 1980. (The results vary with case sensitive, but the overall trends are clear.) The horse has bolted, and you can shut the barn door if you want to. The peak of May I have corresponds to my friend’s father’s school years, and the rebirth of Can I have corresponds with my friend’s school years.
Most comments about (other people’s) grammar are more often about meaning, usage, variety, formality/informality, spelling or punctuation. Speaker English native make rarely mistake grammatical.
Like it or not, when older (usually male) people (including me) say X is wrong, you should say x or Y, they are almost always on the wrong side of linguistic history.
I remember teaching a lesson about this during my first stay in South Korea. I said (to summarise) that according to formal English, can means ability and may means permission, while according to normal English, can means either ability or permission and may means permission. I’m sure my friend’s father wouldn’t have agreed with me.