My GIRLFRIEND has over protective parents and she wants me to kiss her in FRONT OF THEM

is this good or bad?

If her parents are overprotective, then they won't approve of you kissing the girl in front of them.
If you do, you behave disrespectfully and you shouldn't be surprised to find yourself booted out the door.
Do not do it!
The girl is presumably quite young, rebellious and wants to prove a point to her parents. Let her do that but without using you.

Sounds dangerous to me. Like she is using you as a tool to display her independence. If they are truly overprotective, you are liable to find yourself without a girlfriend.
Be careful.

It's quite possible her parents have good reason for being "over protective." - perhaps she has proven herself untrustworthy at some time before you came on the scene.
Wanting you to kiss her in their presence sounds like a set-up to me. You might just get booted out the door by her father.
If she has so little respect for her parents she will have little respect for you.
Being a gentleman will win them over faster than being the anything else.

Do you mean making out like wild chimps or a peck on the lips or cheek?

i'd say a no no to that. If she wants to show her stand i'd rather it be through her not you. You always want to be more respectful to be respected especially by protective parents.

It depends. Is she a good kisser? Are we talking French Kissing or kissing cousin kissing? Will she be wearing lipstick? What's her breath like? These are critical questions. Seriously, no need to let her antagonize her parents while using you.

no thats harable

Depends. If she's 14 they are perfectly within their rights. If she's 24 they should probably relax a little.

Do her parents like you?
If so, go for it, but not like full on snogging.

Start off by a kiss on the cheek or so, then immediately judge there reaction to it.

If they seem they don't like it, don't do it.
If they do, gradually increase the affection to a kiss on the lips.

If you do make sure it's a church kiss & not a full on toungue job!

I don't know, you should ask her about her reason why she justifies this... Then decide, cuz if shes just trying to prove a point, then its not worth the effort, or maybe her parents say that if someone truly loves her, they'd kiss her in front of them.. I wish I could help you but thats the best I got.