Is a player allowed a cut of their own deck after opponent shuffles?
The opponent always has the last touch on the deck. It does not matter if the opponent shuffles or cuts, you may never “recut” your deck.
This rule was changed a while back as previously you could recut if your opponent did a shuffle. The rule changed around M10's release if I remember correctly.
Is a player allowed a cut of their own deck after opponent shuffles?
And the reason for this change is that, if you'd be allowed to cut your deck after your opponent shuffled/cut, then you'd still be able to cut to the correct card. (If you'd be trying to manipulate this.)
Is a player allowed a cut of their own deck after opponent shuffles?
If there's any doubt - I have seen a player do exactly as Drijvers described. Said player was DQed, and you of course should do the same if circumstances are sufficiently suspicious.