I can't think of any pubs that would allow punters to play loud music on their phone/tablet. I suspect the statement from Wetherspoons is just a PR thing.
"Wetherspoon pubs are an oasis of tranquillity" - Jesus, who are they kidding? I pop in to 'Spoons from time to time but in many, but not all cases, they are busy because they are only marginally more expensive than a 2L bottle of cider on a park bench.
If people want a phone free experience, go find a Samuel Smith pub. 5 Years ago(?), I was running early to see a customer and she was running late. I had 30 minutes to kill and decided to pop in to a pub. It was a Samuel Smith, about 1 o'clock on a Saturday afternoon. There were 3 customers in the pub. I purchased a pint and took out my laptop to do some email work. An apologetic bar man approached me and told me that I wasn't allowed to use my laptop (I wqsn't making any noise). I asked if I could use my laptop in the empty garden- nope. He went on to say that the chain/brewery policy is that you cannot use laptops, tablets or phones (period). If a punter receives a call, they are expected to walk out to take the call.
I asked why they do not have any signs to let prospective punters know. He pointed to a sign on the inside of the door, I replied that, perhaps, the sign should be on the outside of the door.
Roll forward, if I unwittingly walk in to a Samuel Smith pub, I do an about turn and find the next nearest pub.