During migrations, I have run multiple servers using the same license. Same with building test servers for deployment pre-migration. But I usally only have them both up for a week at most while they're migrating before the old server is shutdown. SW-Soft hasn't said anything yet.
And given the problems they've already given us just trying to get someone there to answer so we can renew licenses (and still they renew the wrong ones), I doubt they watch them too closely, let alone answer in time to give me a test license (which they haven't in the past).. I don't really see this as violating my license, just that I have no other option. *shurgs*