Some people might think this is cruel,
No, I KNOW it is cruel.
Why as an owner would you not simply avoid having the problem in the first place by keeping food off the counters where it is accessible to large dogs? I grew up with a Great Pyrenees which is a LOT taller than a lab and we recognised that if she could reach something it might be a temptation. The few times she did get something -- once, an entire tray of cooling buns from the over -- we laughed at our own forgetfulness and these became much loved stories that we still retell even though that sweet dog has been dead for nearly 20 years.
Responsible management solves more problems. To me counter-surfing is an OWNER created problem, not a dog training problem. If there's food out, an untrained dog is going to try to get it. :sl*p: So: gate off the kitchen. Watch your dogs more carefully. Train them to wait outside the threashold of the kitchen. Crate them when you are in the kitchen. Take the time to teach an adequate downstay in their beds so they don't countersurf.