For payroll reasons, most venues in my area prefer to have the cake cut between meal courses, or immediately after dinner. I side with the venue on this; there's simply no good reason to keep the servers on the clock longer than needed.
Other factors to consider:
1.) The structural integrity of cakes does not always last the entire night.
2.) Buttercream frosting does not preserve well at room temperature for more than a couple hours.
For what brides pay for their cakes these days, I feel much better knowing that they're cut while everyone's still there to enjoy them. At my events, nobody leaves after the cake cutting.
Other factors to consider:
1.) The structural integrity of cakes does not always last the entire night.
2.) Buttercream frosting does not preserve well at room temperature for more than a couple hours.
For what brides pay for their cakes these days, I feel much better knowing that they're cut while everyone's still there to enjoy them. At my events, nobody leaves after the cake cutting.