It's a fairly common occurrence (I think) that when you are running a query against some store and there is nothing to filter by, you get all the results back. Now the client has to sift through the result set and find products with an empty feature list on the receiving end.
The fix is to add a "no features" placeholder feature and look for it when you are trying to find plans without any features.
The fix is to add a "no features" placeholder feature and look for it when you are trying to find plans without any features.