http://techdirt.com/articles/20100606/2306089702.shtml

Some small pubs and restaurants will definitely gain. Though the music industry need to think again about their music fees. They charge too much. Wetherspoons pubs have no music and so the industry loses out. If they stop music being played everywhere people will barely hear it except on TV and it may harm music sales overall.

I believe that in Wetherspoons' case, it's not about paying for a license, and more because Tim likes people being able to talk. You'll notice that even the bandits are normally either silent or very quiet in them (Lloyds bar excepted)

That could be the case, plus their pubs are pretty busy all day so do not need any ambient background noise.