I would like some more examples as I have just stumbled across the irony of the legal situation here in the UK.

Singing or playing 'Slane' for example as part of a religous service, in a cold, ill-lit church, with no sanitary facilities or emergency exits, is public entertainment but exempts the premises from any licensing requirement.

Singing or playing the same tune for the sheer pleasure of doing so, in a cosy pub which is alrady subject to many safety inspections and conditions, is illegal without the licensee paying for a Public Entertainment Licence.