Yes it does. Say you're an agency sending email on behalf of several different organizations. If you export one to send through CampaignMonitor (usually list or domain approval related), the employee who pulled the HTML gets their hand slapped by the IP ban. It's less likely to happen next time with a different campaign or different client. I haven't actually experienced the IP ban but I've sent for the same organization through multiple ESPs without quitting one for good.
Even if you are a single organization user and leaving for good, you might do so gradually or perform test sends first. Speaking from experience again.
