According to the NY State Rent Stabilization laws, a roommate is distinct from a subletter, and a renter has an absolute right to have a roommate. The landlord is not required to approve the person, and only has to be notified.

Any court looking at any proprietary-lease clause about roommates will look to that established tenet (note: "tenet," not "tenant"!) for guidance. It's hard to imagine a court would find forbidding a roommate acceptable -- if it were, you couldn't a significant other move in with you.

Condop?
Dan, where exactly do you live in the condo or coop?
Condo apartments can be freely sublet, and there is no way your proprietary lease states that sublease require board permission and can only be up to 2 years.
In the coop The proprietary lease usually provides that the shareholder and members of the shareholder’s family may occupy an apartment, and Section 235-f of the Real Property Law (the so-called “roommate law”) provides that every residential lease entered into by one tenant “shall be construed to permit occupancy by the tenant, immediate family of the tenant, one additional occupant, and dependent children of the occupant…” This law has been held to be applicable to co-op proprietary leases. Therefore the co-op board may not prohibit shareholder from having a roommate.

I live in a cond-op. Despite its name, to me, it's pretty much a fancy name for a co-op. In any case, the board instituted a new rule requiring the shareholders to "register" their roommates with them. And, get this, our management company wants an occupant (non-owner) registration fee. I am starting to believe when there's nothing to discuss at board meetings, things start to get ridiculous.

You have to tell them the name of your roommate if they ask and nothing else and there is no way they can legally charge a fee. get on your board and help them/. they need it.