They are actually putting down ice melt which is very different from salt (which looses its effectiveness below 15 degrees, causing a lot of damage when the water refreezes). However, in all honesty, you'd be lucky to not have your warranty voided no matter what you or anybody else does. Placing concrete is such a science in itself that they can find pretty much any reason to void your warranty. I managed to have my builder lift my driveway, but only after proving that it could cause tripping and was a safety hazard that I could not have possibly caused. Still, it took over a year to have the issue resolved while they tried to find a way out of it.