I would like to suggest a couple of ideas that may help with the problem of theft or deception by sellers of add ons for Dolphin.

1. Why not have a potential software developer have to apply first for testing and approval of their software. If a test server were deployed to test the add on, it would do several things.
a) Prove that it really works
b) prove it is easy to install - less demands on technical support.
c) validate who the author of the code is.
d) prevent anyone else from offering see more it later on
e) prevent crooks from easily offering stolen goods or faking software altogether.

2. Another option may be to encode add ons so that they only have a 30 day free trial capability and enforce that all add ons be sold this way. Personally I think this would be easier to crack and also delays earnings from reputable software designers, but it is somewhat of a solution.