The Sam Smiths' ban is a limitation, Roger, and an unwelcome one at that (by us folkies). But in the context of your original question, i.e. whether "protections in place to protect the composers, publishers and performers of songs - are in danger of generally preventing us from being able to sing or of seriously limiting what we can sing and where", I argue that it is not a serious limitation, because there are alternatives. No impending end of the music or of the singing is forecast.

The Sam Smiths ban was a business decision on their part. The public now can vote with their feet and prove them wrong - or right.