The FCC does a lot of threatening over this, but its history is that it will do little if anything to those who don't comply.
The FCC mandated way back when that all companies make their PBX/CBX systems comply with CallerID rules. To this day, there are many companies that don't deliver CallerID when they call you. The FCC has very few staff in the enforcement division and are very poor at enforcing their decisions.
