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Austin's Rugby scene isn't exactly backing the Elite as is. Some are openly hostile. Which could be the source of this rumour as a means of subversion on certain peoples behalf. But say if it is true they have Cashman Field in Vegas that would work out well for them. It's being reconfigured for Soccer/Rugby at present at being primarily used for Baseball up until it's previous primary resident moved to a new stadium. Nothing wrong with the facility either. Actually looks really nice. But the Baseball team didn't own it outright and weren't super happy about other sports being played there.
The other issue for Austin is that it's Rugby scene isn't all that big to start with. Two primary clubs plus UoT. Both Houston and Dallas have much larger and growing scenes. Honestly, Austin wasn't the best place for a team to start with.