Looking for zen

Today school was closed (yuck) and Monday school is also closed (double yuck).  Yesterday was the little ones Valentine's Day party.  She asked me to come to the party.  The room mothers had asked for donations for the party (I did water bottles) and there was a sign up for 3 volunteers.  That had already been filled by the time I opened the email. Anyway, with the Halloween party I asked if it was alright for parents to attend and was told it was fine, Christmas party also asked and told it was fine.  This party had sign ups for volunteers to be able to attend so when I dropped off the water bottles I asked the teacher and she seemed distracted, busy, and frazzled told me to ask the room mothers.  I had sent them an email so when I got home I checked my email and was told that no I could not come, the principal and staff had decided only the 3 who had signed up to be volunteers could attend.  Hmm, what is the deal here?  Politics between the PTO, home room moms, and teachers?  Since I had asked the teacher and she gave me a different response I know the answer I got from the home room mom was bull.  Just say that the room is small and too many people make it difficult to control the kids.  Say thatI have no idea, but what made Valentine's Day different from Halloween and Christmas?