Very true.
A mod can completely void your warranty, if someone (a dealer) believes it is evidence that you have abused your vehicle by taking it off road. Yea, I know its a Jeep, but the federal law and court cases don't have a Jeep exclusion. BTW, Mustang owners have the same grief over mods that might be considered evidence that you abused your vehicle by racing it (even if you only put on the mods because they look cool).
Most dealers will look the other way, unless you really have been overly abusive with your Jeep off-road. But there are some who seem to delight in ratting you out to FCA. If you have a local Jeep club, that's a good place to learn about such (that's how I found out which local dealer to avoid).