On the subject of kashrus:
I heard this from a rav who was at a wedding. The story happened to his wife.
Basically, she wanted to know if something (I think the barley in the soup) was yoshon. she went to the kitchen and asked. No one knew. She asked to speak to the rav there, and surprise surprise, there isnt any. She called the certifying agency who of the caterer and they said they only gave hashgacha on the food until it left their facility. This rav said for a small amount (under $500) its possible to call the OU and hire a mashgiach for the night. He did this when he made weddings and was very happy.