Why don't you get in there and ask them.
Like this
YOU: "Breaker Green Dot, Breaker Green Dot. Ya got your ears on Wal*mart, C'mon?"
WAL*MART: "How did you get on our channel?! All associates, check for a missing walkie"
YOU: "I'm just curious why you're using narrowband on blue and green dots?"
WAL*MART: "Get off our channel. This is our channel. And give us back our walkie talkie!"
YOU: "But are you aware that you aren't required to be narrowband compliant on those two frequencies? I'm just trying to give you some friendly advice"
WAL*MART: "Sir, I'm not going to ask you again. Get off our channel and give us back our walkie talkie"
In seriousness, and in addition to replies #2, and #3, I don't think you can buy a MURS radio that has wideband any more.
If they had one of the grandfathered ones from a hundred years ago, great but I seriously doubt that they do.