When's the last time you heard of a state agency arresting a shop/retail owner for not reporting the taxes they collected or for not collecting sales tax? There are some, I'm sure, but not that many. If a retailer decides to pocket the money kept for taxes, plus the administrative sum they are allowed to keep, then they should be prosecuted.
You put people's money back in their pockets and I gurandamntee you that there will be a clamor. If people were suddenly required to pay quarterlies or monthlies, there'd be a revolt that would make the Boston Tea Party actually look like a party.
the last time I heard of some shopowner getting busted for not forwarding the taxes they collect is about the last time I heard of someone going to jail for nonpayment of federal taxes. as you haev said before - fear of government guns is mighty persuasive.