Everybody (official Apple retailers, technicians, stores, and Apple themselves) seems to make up their own restrictions on this topic. There are numerous posts that have plenty of conflicting views. So basically, go searching around til you find someone that guarantees you still have the warranty or something, and in the case that you need your MBP worked on, don't say a word unless they ask.
Or just do it yourself, and if everything is done correctly without any harm, they probably shouldn't have a reason to ask, if/when you happen to bring it in under warranty.