It’s not easy to distinguish between legal and illegal tying, but that doesn’t mean that disclosure to the buyer is an adequate defence. More commonly, the seller would argue that they lack the market power of which tying is said to be an abuse. https://en.wikipedia.org/wiki/Tying_(commerce)
Yes I should have added the caveat "in an otherwise competitive market". If there was only one seller of houses then the tying would indeed be a problem.
