Hello y'all

i got a order for a wedding cake that's going to be all buttercream iced, the reception is held in a wedding hall and i was planning on setting the cake up an hour before the reception starts, done this many times before, but here's what i'm worried about;  at a wedding when the party starts and people start dancing and celebrating the hall gets very warm. the cake will be cut at about  8pm and since the wedding starts at 5 pm it has to stand for 3 hours... will it melt ? i am planning on using the half butter half shortening recipe

If the reception has air-conditioning it should be okay. Outside in the sun would be a different story.