Mr. Falcon said: praying discreetly is one thing, but praying out loud could mean that you're an asshat.
Bingo. Actually, even when I was a Dub, I don't recall any other Dubs praying out loud in a restaurant. They would close their eyes and say a silent prayer of thanks, and I don't see anything wrong with that. Sounds like some dipshit is trying to be a Superfine Apostle by drawing attention to themselves. If they only knew how stupid they looked.............
On a side note, I don't recall Jesus ever praying out loud, except for when he was dying (and I think that's perfectly understandable). Other than that, he always prayed in private or just in front of his followers didn't He?