Understandably, not the first time for this question.

It is not impolite in some social situations - eg between younger people to each other generally or at least in informal situations (although they would likely also say ‘on ‘ instead of nous),  or by an older person to a child. 

As a drop-down choice, it is not incorrect, although not the first response you might think of. 

I guess as a teaching example, it is a chance to come across this possibility, but it might cause less consternation here if it was ‘vous’, keeping the focus on the negation and verb conjugation required - as without explanation it could result in misunderstanding the important French ‘politesse’.