As i understand vehicle warranty - a modification has to have relevance to the fault - it is an unfortunate dealer tactic to blame a failed engine on a non stock floormat
So if you make a buthers job of the fit and then the key in / door open chime doesn't work or the interior light doesn't operate - well you have ceated the problem and have to wear it. Its exactly the same with any electrical mod - driving lights, CB radio, dual batteries, fridge, stereo, compressor etc etc.
I think its a decission we modifiers have to make.... but even on standard vehicles i've heard of bloodyminded dealers being a PITA so i don't think chimebuster makes any difference.
Fit it as specified and IMO a dealer would have VERY difficult time blaming you.