Would you allow your preschooler to go for a sleepover?

Pre school kid has alot of stuff to prepare for sleepover and some of them not even 'graduate' from potty training. Sleepover for preschool i think will be a huge challenge both for guest parents and the host. What if they cried in the midle of the night and ask to go home? And what if my kids have some allergic? Too much drama to handle i guess i'll give the permit when he is older and more independent.