to add....
When the economy tanked, there were issues with a lot of shady "pizza and sub" businesses popping up and soliciting at the hotels for business. Sometimes these people were reselling frozen grocery store pizzas for a large markup. sometimes they were fronts for credit card scams. and many times they didn't have the proper legal health or business credentials to operate these businesses.
There were also a few reports that some of the people where using the distro of the flyers as an excuse to visit a hotel and were casing the joint trying to get an idea of which rooms where occupied or which guests were currently away for other more serious crimes.
As a result, many of the more upscale or legit resorts and hotels have tried to crack down on the practice, both through the delivery of flyers, and also in some cases by limiting what offsite locations are allowed to deliver food to the resort.
In general, to protect yourself, stick with the national chains or the names you recognize (Such as Flippers or Gordino's around the Disney area)