Since our water is so terrible in LA, it's normal for me to buy 1 or 2 gallons of drinking water on each visit and have them under the cart. They are also under $1 so it doesn't blow the budget.
One of the stores I used to work for in CA has a mirror system at each isle allowing the 'hight-challenged' checkers to see BOB (bottom of basket).
While the bagger may walk away if he sees me with only a few items, the checker may often spout, "Bob's your uncle" or, "What about Bob?" That's a sign for the bagger to grab the items under the cart. They know the shoppers usually have fewer items in the cart, so you are more likely to not be checked if the cart is full, I think.
I did 2 shops a week for this store over 6 months and had the BOB item only missed once. On that occasion the checker was actually having an emotional meltdown and missed every point on the checklist, however.