I came close ... 12 lbs. over my lowest post-op weight before I slapped myself upside the head and stopped the stupidity of eating junk and grazing.
You can definitely "eat around" and "drink around" your sleeve if you want to. A sleeve is NOT foolproof. But fortunately, if you start eating right again, and exercising, the weight will come off easier than pre-sleeve, due to the restriction you get.
Take advice from someone who tested the limits of her sleeve and is now paying the price (dieting again) ... don't buy/eat junk food (and junk drinks, like booze/milkshakes/frappucinos) and don't graze. Just following those two rules will definitely help you avoid weight re-gain.