The act of grabbing a bunch of stuff you may never use or eat, just because you are not paying on a per-item basis.
If you eat, use, or directly pay for all you take then Buffet Effect is NOT an applicable term
If you paid over $35.00 per person Las Vegas
and don’t eat everything on your plate before getting a new plate, then it is NOT the buffet effect. This falls under “getting your money’s worth”.
“Those kids have four plates of deserts at their table. To avoid the embarrassment of Buffet Effect, those parents better make them eat all of it”