I don't know that there are more generalised events. Sessions at any rate tend to be advertised as Irish, English, French, Swedish, whatever. Most are flexible to some extent over nationality of the music, especially with visitors or inexperienced players, who may well have learnt a tune and have no idea of its provenance. Irish sessions do tend to be a little stricter!
Our English session is "English till 11 o'clock" after which anything goes.
And in a pub you can't expect your "audience" to be purists in this respect, they may not even like the music, so it's always good for public relations to play requests if you can (although you might want to leave songs like the (London) derriere till later in the evening!).