I just experienced this:
Set up a performance of sounds.
Then wanted to copy an effect slot from a rig in another performance. I used cmd c for this.
Paste (cmd v) in the appropriate rig in the destination performance.
Turns out i copied the whole performance, with NO way to undo it. I did NOT store in any way.
Days of work and careful listening, leveling etc gone in one mishap.
F**k