Commercial real estate, is this legal?

Legal, yeah. Enforceable? Probably not.

I don't see how that would be enforceable.

What if their broker dies and they close up shop?

This is anecdotal at best, but in a real estate listserv I'm on, there was a recent discussion about a trend going around in residential real estate where brokerage companies were paying homeowners a nominal amount (a few hundred dollars) for a recordable agreement that if they sold their homes anytime over the next 40 years, they would use that brokerage exclusively in the sale.

In response to this predatory practice, there has been a uniform act drafted to prohibit such agreements and that act is in some stage of passage and becoming law in about 20 states at this time.

The point being, that if this practice isn't patently illegal and unenforceable on its face in a residential context such that 20 states feel the need to pass specific legislation to protect against it, then I question whether it would deemed illegal or unenforceable in a commercial context, where the courts are generally less protective.

Ultimately the legality in alot of these situations is determined by how much money each party is prepared to spend on legal fees.

Thanks for the responses.

I think most of y’all are right in that I can’t find any law that directly states this is illegal. However, I have a hard time believing this would hold up. It’s basically holding someone’s asset hostage.