GUEST
It has already been explained, but as is usual with controversial threads on Mudcat it turned into a slanging match which somewhat obscured the OP's original intention.

A 'session' to most people in the English-speaking folk world loosely means a gathering of performers for the fun and craic playing together and unpaid. However some enterprising landlords have seen how this can draw in the crowds and pay maybe half a dozen performers to come in and entertain. This is often advertised as a session but is anything but, in other words a fake session. (Before anyone jumps down my throat this is not a criticism. I've done the fake session myself on occasions. Each to their own!)