I managed to find a thread from 2009... not great but at least a bit more recent. Hope it helps. Perhaps other members will know more
https://www.casinomeister.com/forums/threads/casino-del-rio.28996/
They are part of the Winner Casino Group - who I think are OK. (I list Winner Casino on my site, but not Del Rio at the moment)
The affiliate program is certified by CAP & GPWA (for what that's worth!) and also Affiliate Guard Dog.
So all in all, pretty legit IMHO.
KK
del rio belongs to the redfinger trading ltd ... which also own winners casino and 7regal casinos they all are playtech casinos... winners casino and 7regal casino offers bonus which is best in the playtech industry they are cashable and 12 time wagering only at del rio is 20x so far i know... very fast pay at 7regal .. 1 day pending and winners casino when u become vip it will be faster aswell..and great vip packages..
I used to play there years ago and always got paid, they used to also be affiliated with Carnival and Tropez, maybe CPays were the group, saying that I have not played in many years and do believe there has been some questionable issues in the past few years.