When at the grocery store is it rude to consume food before you buy it?

I was at Wal-Mart the other day and I noticed someone opened up the chicken nugget bucket and was mowing them down.

To me, that is a NO NO. To me, that is rude. I was taught that you wait to eat or drink or open anything till after you've paid for it when you're at the grocery store.

What say you?

More From 98.3 The Snake