AFAIK, direct trading exchanges like LocalBitcoins do not need any license to opearate as they do not touch FIAT themselves. They operate as an advertising platform similar to craiglist.
But the LBC itself holds the coins in escrow during sales. They're not just linking buyer and seller, they're participating in the sale. Casascius was shut down without going anywhere near USD.
But, AFAIK LBC does not have any money transmitting sort of license. They operate like online ad platform. Hence we have seen many cases where authorities took action against high volume sellers on LBC, but there was no action against LBC itself.