Unlike paintball, "tippmann" won't be the only BB manufacturer available to us.
If people start charging for BB's, people will say "fuck you" and buy them the same way we've been buying them now.
Alternatively, they COULD wind up not knowing what we pay now, and charge LESS for BB's, and it could even be a good thing, if they think they're making a profit.
I can only really forsee it being a business in the paintball sense if places just rent the guns out to people. Having airsoft specific fields if everyone can just buy their own gun (even IF you make them buy your BBs) isn't going to be hugely profitable, otherwise wouldn't we have more places to play as it is... :-?
Tippmann products would have to be EXTREMELY good, and highly sought after (and probably too expensive for the average person to buy), in order for a demand to play at a rental only venue to grow.
And at their projected $150 price tag, I'm guessing that won't be the case. If people can get one for themselves and do it their way, they usually will.