I see the Czech airline policy is a 7KG carry on. I have a compact camera backpack that is quite heavy (very dense) due to lenses and camera body. It looks no larger than your average "student" backpack. I will have no other carry-on with me.

Do they enforce the 7KG limit? There's no way I can check 10K worth of camera gear, so if they don't let me board with with it I'm not sure what I'd do.