Frustrations

One part of subbing I don't like is when a teacher has different rules than the main office. Here the main office says no gum. 

This teacher? Doesn't care. 

Which results in me tells the kids to throw their gum out, and then I get,  "But Mrs. X lets us!!"  

My usual reply? "I'm not Mrs. X am I?"

They really don't like that reply. 

But gum? Hate it!! Makes people look like cows chewing on a cud. Not attractive at all. 

Subbing would be easier if ALL the teachers would just follow the school rules.