It depends on where the fan is in the system, and what kind of tubing. My small laser has the fan mounted at the exhaust port in an old window. The whole system is suck, rather than blow. And for tha cabinet and laser, its more than OK. My big chinese deally... It came with a fan that is much more suited to be mounted on a tarmac, or in tis case, on a pedestal right behind the machine with a lot of blowing out the exhaust port. And with the plastic type hose that came with it all (big 8" diameter stuff) you get all sorts of smells that leak through.
So that would really depend on the blower setup. Some of the chinese machines exhausts have issues blowing out a candle at 5 feet, let alone moving air, and thats if the buyer actually bundled it all together. Ive seen more than one home shop skip importing the blower only to ad some bathroom exhaust setup in the works that couldnt clear a fart from a 1/2 bath.