I would be fine with creating a burner gmail address for this purpose.
Though this is perhaps more friction than we want for the voting process?
It also wouldn't be too difficult to self-host this and throw it on an authenticated route. I'm not very familiar with the architecture of lemmy, but in theory we could leverage our existing username/password to access the RCV app.
After thinking about this for a few minutes, this is almost certainly over-complicating things.
Why don't we try disabling anonymous voting and have folks input their usernames? I think we can trust that people won't try to game the system.