Excuse You

Mom and I were doing a little garage sale and thrift store shopping today. We were looking for a bike for Colton. Anyway, while perusing the wares at our favorite local thrift shop I heard a few things I really didn't care to. First of all, one of the workers came by and said good morning. Then she proceeded to say she didn't feel well and burped loudly. I was a bit surprised, but just laughed it off. A few minutes later I walked by an older couple of customers. The man suddenly belched even more loudly than the worker. He did it twice more in the next 5 minutes. My mom even said she could hear him across the store. I wondered if I had missed the sign that said, "Burpers welcome" on the way in. Do manners not apply in these establishments?