yes. depending on how it "looks", they will be suspicious and will weigh it. A large duffel bag, roller board or large back-pack is begging for a weigh.
A laptop bag, small back pack or purse hardly elicits a weight check.
I suggest you carry a coat with many big pockets, wear your heaviest items (coats/sweaters/shoes), carry in hand your heavy electronics (laptop/camera/chargers etc.) , put small and heavy things in your coat pockets (chargers/colognes/books). Only at check-in, and at boarding.
Once you complete check-in, you can repack before passing security, and once you board, you can repack on the plane.

And, just switch to a lighter luggage bag if you want to avoid check-in fees.

That is how I avoided baggage fees on these airlines in the past. (I have outgrown LCCs unfortunately)