I can almost guarantee that's what you do. I'm comfortable enough that I would easily bet money on it.

While other names providers won't have a subsidized iPhone for sale to lock customer to their network, they'll be more than happy to sign you up for service with your own phone. I've never heard of anyone turning away a customer bringing their own compatible phone in the US or Canada.

Also, locked phones may work (all I've tried have worked) on the network they're locked to, generally even through an MVNO, including with PayAsYouGo or any other plan. Phones can be network locked, not simply provider/brand locked which they'd do with a SIM lock for GSM. And definitely not plan locked. It's just when you buy new you're usually restricted to a set of specific plans - but even there you have wiggle room sometimes as long as you're committing to an equivalent contract term.

Up here that means SpeakOut Wireless and Petro Canada (MVNOs) work with ROgers network, etc.