The Fear of voiding your warranty with aftermmarket parts

I have occasionally read that some of you have taken off your aftermarket parts before you go to the dealership for warranty work. Some of you are afraid that it will void your warranty.
I was at the dealership today for warranty work and decided to speak with the service manager about this subject. I asked him if I WERE to purchase an aftermarket (non nismo and not installed by the dealer) CAI, throttle body spacer, and exhaust, would that void my warranty.
He Informed me that He has many new car and truck customers that install these type of parts on their vehicles and have never seen a direct problem arise from these.
He did not see a problem with anything I mentioned.
He gave an extreme example of a guy who put a nitrous system on his 2005 maxima.
He came in for a problem with his maxima and removed most of the nitrous system but left some of the injectors. They decided to go ahead and fix the problem once but told him they would not do it again.
This dealership seems very progressive. My advice would be to ask the service manager the same question I did and see how they respond.
If you don't get the response you want got to another dealership (if you are lucky to have another Nissan Dealership in your area.)
I guess I got lucky. The Dealership is Davis Moore in Wichita, funny thing is I did not buy my truck from them.