VERY subjective. I would say for most friendly games, check-raising would be out, but it really should be decided beforehand. If it's available then it should be able to be used with no bad stigma.
I play friendly games, but we're all frequent poker players. Playing a poker game without check-raising to us is like playing a game of chess with no knights.
If you play a short-handed game and don't allow check-raising, the positional advantage/disadvantage becomes enormous. The button rotates, so each person gets an equal number of shots at the late spots. WIthout checkraising, however, it creates a very big disparity in the advantage from hand to hand.
For me poker is war, friendly game or not. That's what makes the game exciting and challenging. If your goal is to be entertained, and smoke cigars and drink brandy and toss some cards and chips around, then I think check-raising sdoesn't really fit.