The only other solution would be if you have the "Make backups when saving tournaments" preference enabled. When this preference is enabled, the software doesn't write over existing tournament files, but instead renames the existing tournament file first, appending a timestamp to the name, and then saves. You'll end up with a lot of files at the end of the night, but they're relatively small and with today's hard drives they wouldn't begin to make a dent in your disk space. Once the tournament is over and you're satisfied the saved file is sufficient, you can delete all of the backup files. Unfortunately it won't help if you didn't enable it.
Thanks for pointing out the change in the Reset button behavior. Sorry it had to be discovered in this way. I'll change the behavior back and add a warning dialog for times when resetting the tournament will disable Auto-save.