It does seem to be a worty cause without a doubt but the small crowd will barely cover Chelsea's expenses and stadium costs....
New England Revs pull their support from the 6 states. Buses from Vermont and Maine are there each weekend game.
The stadium is in the middle of nowhere with no public transport from Boston or Providence (which, in Rhode Island is actually nearer to the stadium than Boston is) for Revs games (trains from both stop right outside for Patriots games) - so given that, plus a midweek game and an $85 ticket.....
There is a large Chelsea supporters club in Boston (by that I mean Chelsea and City are the biggest group going to the Banshee to watch games, Liverpool have their own packed out pub) but this game will be a flop attendance wise.
Good game practice for Chelsea but would have been better asking Brentford for a behind closed door game and staying at home.
Isn't the game being played in Foxborough with a capacity of some 60 odd thousand?
Edit: I just had a look, and I can tell just by looking at the stadiums wiki page that there are different attendance capacities for the Pats and soccer games. Do you know why they've closed off parts of the stadium for MLS games?