You could be right in your assumption, but because I've worked with iNetBet so long, have had such a great relationship with them and trust them as much as I do.... I would look hard for alternative reasonings for this before I'd assume iNetBet is doing this. I really don't think they're THAT stupid. They've been in this business for too long, and are too active on forums like Casinomeisters, to be as stupid as to do this forum spamming thing. Really...
I don't know enough about
SEO let alone blackhat
SEO to really offer any suggestions. Unless someone is trying to discredit them and make them look bad. That's always possible too. Afterall, iNetBet does have the best reputation amongst all the RTG casinos in my opinion.