Commendable post, and I hope it gets 'stickied' for future reference.
I'd just like to reiterate JAMJTX's position that it's good advice for commercial dojos, with the reminder that not every newbie is looking for a discipline for it's 'martial worth'. Face it...many people that are very happy with their arts are not concerned with the martial side/potential.
As for scratching a bit deeper, to find non-commercial training, I think it's a bit trickier to go about verifying the 'credentials'. I wouldn't suggest the 20 questions approach if applying to koryu, or private dojos. Research is good, and an openness to answering questions is always preferable...but the 'contract' is different...and different rules apply.