If they didn’t qualify, the liability can reach you. Where a rebate is credited to a purchaser who wasn’t entitled, the purchaser has to repay it — and where the builder knew, or ought to have known, that they weren’t entitled, builder and purchaser are jointly and severally liable.
“Ought to have known” is the problem. The first-time buyer programs turn on a four-calendar-year ownership lookback that includes the purchaser’s spouse, measured on the date ownership transfers. You have no way to verify any of that. You’re relying on a declaration signed by the person who benefits from the answer, and then carrying a share of the risk that it was wrong.
CRA guidance is explicit that where a builder pays or credits the rebate, both parties should review the eligibility criteria. That’s a review you’re not equipped to perform.
That reframes it from “you might be liable” to “you’re being asked to certify something you can’t check.” Considerably more persuasive to someone deciding whether to credit.
When you credit the enhanced rebate, the two portions come back to you by different routes. The 8% is deducted on your GST/HST return. The 5% ONHAP cannot be — you remit it to the CRA and recover it separately from Ontario, after the purchaser’s eligibility has been assessed.
That gap can run to several months, and it is contingent on a purchaser meeting conditions you have no way to verify.