Right, gate-checking a bag means the agents will put your bag underneath with all of the other checked baggage and it will be on the carousel. It's different, as you probably know, from gate-checking baby seats/strollers. Those will be on the jetway when passengers get off the next stop/final destination.

I would NEVER put my laptop in a checked baggage. Airlines do not cover electronics if they are stolen or lost or damaged.

If all else fails, take the laptop out and stick in the pocket in the seat in front of you and make them only take the bag to check. Good luck!