Realistically the Dealer can void it for what ever they want. The words "OR POSSIBLY CAUSED THE PROBLEM" means they can make up whatever story to not have it covered and or void your warranty. If I was you and you ran into a big issue just make sure you convert it back to stock, just to be safe. If its for maintenance related issues you shouldnt have anything to worry about. Just set your tune to "stock map" which most tunes have. For example the JB4 stock map is map 0. Hope this helps
A/W E92 335i M-sport with JB4 G5 ISO/ E40 WEDGE PERFORMANCE BACKEND FLASH, Alpina TCU flash for AT/Switch-tronic +AR Downpipes, Stett gen 1 intake, Wagner-Tuning FMIC+RB Turbo setup/ RB PCV Valve+ Akro exhaust+60% E85/93 mix,+ HRE P40S wheels, KW coilovers, M3 sways,+BMW performance CF Mirrors, BMW Performance CF deck lid spoiler,+ CF interior trim, p3 vent boost gauge,+ LUX angel eyes (11.73@119mph on street tires) NO METH!