In AmE, you only use the proposition 'on' with nouns that refer to groups of people ('team', 'board', 'commission', etc). Am I right?
Can I use 'in' without sounding like a weirdo or, at least, a foreigner (for the purposes of this question, we put the accent aside)? Is it mandatory or just an option? If for some reason you need an example sentence, here it is:
Mr. Smith is on the team/board/commission.
Best Answer
Be very leery about using the word only when giving rules about English.
You wrote:
The three example nouns you provided – team, board, commission – indeed typically use on instead of in. However, I thought of three other nouns (there are probably a few more) that can refer to groups of people – group, society, and clique – and the preposition in sounds more natural than the preposition on for those nouns.
Therefore, I think we can say it's something we must evaluate noun by noun; it's not as simple as saying that "all nouns referring to groups of people take 'on' as a leading preposition."
Clearly there are some overlaps in the definitions of these words; from Macmillan: