I play at Stones a bit, and last time I was there, there was this dude with a laptop open on his drink cart playing a few tables online on the side while playing live. They are very (too) lax about technology there.
This is also not uncommon. I've seen similar at Oaks, Bay 101, Wynn, Casino Arizona, Commerce, and probably others as well. I tend to believe that it shouldn't be allowed, if only for the pace of the game, but it's not unique to Stones.