Can a buyer insist a non-compete cover more than the exact activities the seller's business actually did?

A buyer can certainly ask for that, but the broader the covenant reaches beyond what the business actually did, the more exposed it becomes to a challenge that it is unreasonable and unenforceable. Ontario courts do treat a seller's non-compete more permissively than an employee's, since it is understood as protecting the goodwill the buyer actually paid for, but that protection is still tied to a legitimate proprietary interest — meaning the products, services, and markets the target business genuinely competed in — not an unlimited restriction on the seller's future activity in general.

A covenant drafted to reach products or services the business never actually offered, or industries it never operated in, risks being found to go beyond what is reasonably necessary to protect the purchased goodwill, which can put the entire covenant at risk in a dispute rather than just the excess portion, depending on how it is worded and whether a court is willing to sever the unreasonable part. Buyers wanting broader protection should think about tying the scope to realistic future or planned activities that were genuinely part of the business, rather than an open-ended description untethered from what was actually purchased.