I don't go to the check-in desk if I'm carrying on.
This doesn't work for international, by the way. But it sure does in the US and possessions. You have your boarding pass already or you get it from the kiosk (automated) and you go through TSA and check in at the gate.
I learned this back before there was a TSA; if you can avoid the front desk do so. There is never an advantage to stopping there so unless you must, you don't.
Nowdays I avoid flying whenever possible as I find being sexually assaulted (virtually or for real) an unreasonable requirement for air travel. Before that time however I was in the air a LOT, sometimes 3 or 4 days out of the week, and I always had electronics of some form with me -- camera gear, laptops, sometimes other computer gear or proprietary stuff (boards for embedded systems, etc.) I learned most of the tricks but the best ones (including the fact that tickets can be franked between carriers) no longer work with the death of the paper ticket and "e-ticket" nonsense. Most people don't realize exactly how badly that change has rammed them, especially when there's a weather or equipment problem. Over countless air miles across well more than a decade in the world of paper tickets I only got actually stranded and unable to get out ONCE. I flew standby on a ticket from a carrier other than the plane I was on more times than I can count and never paid a fee for it either.
I've been "sized" several times with carry-on items but never had a problem with being weighed.