Doesn't matter why the person in front stops, thats the whole point of Proper follow distance. It could be something you dont see, object in road, ect. If they lock them up, and you run into them, thats your fault.
Guy in front might be stopping for debris, animal, or other hazard.
Funny story; Many years ago, working on resurfacing a rural 55 mph roadway, 2 lanes, 11' wide, no paved shoulder, going to 12 ft lanes with 2 ft shoulder. Daily flagging operation, with proper signage and all. One local "kid" on a crouch rocket would sit at the flagger station, reving the rice rocket anytime he got stopped, every day. One day, paving, hes behind a load of asphalt, doing his typical BS, they released traffic, hes behind the dump truck. Truck does up to to the front of the paving train, kid on his butt, and dump truck pulls into the lane closure to back up.
Kid follows him into lane closure and hits the gas as the truck stops... He slids, flips, and goes butt down, across about 100 ft of asphalt in street pants

. We all laugh at him and call him a idiot. He gets up kinda slowly, and starts cussing and threatening about calling cops. Sure, go ahead; proper follow distance moron. You have road rash, a trashed up bike, and now your skinny butt wants to talk trash and threaten 13 grown men in the woods.... When I yelled "lets make him squeel like a pig", he decided retreat was the better part of valor