unionizing doormen?

Hi,

Our current management company is an affiliate of the conversion sponsor.  I am uncomfortable with this as a board member, but they are about 1/2 the cost of 3rd party management companies we have considered as alternatives.  This will presumably continue to be the case until the sponsor's interest has dropped below the point where he wants to continue this subsidy arrangement.

Our condo currently has non-union employees. One of the sponsor's other arguments is that if he is no longer involved as the management company, the union will convert the doormen and our costs will sky rocket.  From my experience with other condos where I own units this seems plausible from a cost standpoint.

(Before you object, we offer health insurance and cost of living adjustments ever year, but I concede we pay less than union.  The main difference is really the potential pension liability since we do not offer a pension plan.)

My question is this: how pervasive is the doorman's union?  Does anyone have direct experience of a building's staff switch to / from union?

Thanks in advance.