A deposit is money you owe until the event happens
When a client pays a deposit for an event that has not happened, you have not earned it. Book it to a liability account, usually “customer deposits” or “deferred income – events”, and leave it there until the event is delivered. Revenue for a single-day event is recognised on the event date. For a multi-day exhibition, recognise it across the days delivered.
Our point of view is blunt: event companies that put deposits straight to sales are running their business on a misleading P&L. They see a strong first quarter, hire for it, and then discover in the autumn that the cash was already spent.