Select Registry innkeepers are supposed to receive a 50% off discount at fellow SR properties - we used that frequently (trying to go during less busy times at the properties), and a few whom we knew gave us free rooms. We gave that level of discount to innkeepers that we didn't know even if they weren't SR, and gave free or highly discounted rooms to many innmates (forum or not). We did have to know they were innkeepers - didn't know about one until they showed up, so I gave the discount then.
We did have an early-on bad experience with a fellow innkeeper - was a PITA guest, added nights at last minute, and I discounted for two rooms for him. He wrote a snarky (but 4 star review) and I questioned my professional discount policy for awhile. But he turned out to be the only real problem child in our 11 1/2 years, and I loved hosting innmates from the forum and not..