Are employers alowed to deduct tips from your paycheck?

On my last check, there was a deduction of $15 saying that it was from cash tips. I make about $3 in tips per paycheck. I am also supposed to write my total tips on the back of my punch out card, which i didn't and never did before. I don't remember signing anything that said the penalty of not filling out the card is $15. This was the 1st time i noticed $15 removed from my paycheck. I work at a Dunkin Donuts at my college and I get paid $7.50. $15 is over 2 hours of work. It is a big deal to me, being a college student with no money. are they alowed to take my tips out of my check or punish me without my knowledge of the possible punishment?