Depends man, are they ignoring you while doing it?
Like, I had one girl start showing me her IG posts of winning a beauty pageant after she replied to a couple of messages. Had another pick up her phone and start showing me her friends and ask if I thought they were pretty, occasionally answering a message in between, one other pulled it out so she could show me comedy vids that she liked and replied tonone message first. But if they pull it out with 10 to go and just start scrolling while pretending you're not there, I wouldn't make a fuss on the spot, but I'd let management know and I'd let other boys know in a review.