New school in my town. Advertises primarily BJJ, also kickboxing and some form of MMA. I'm thinking of attending the BJJ as I have only 'stand-up' skills (Karate, Ba Qua). Not interested in games, just practical training. My question is:

What clues may there be if this is for real or somebodies BS or false advertising? What are some of the warning signs or good signs to look for?

Find out the instructor's name, it should be relatively easy to check and see if he is legit.

Any legitimate BJJ instructor will have an easily verifiable lineage.