I did a bit reading about this a while back as I wanted to replace the tatty keyfob with a new one.
Cutting the blade isn't much hassle but all this will do is unlock the doors and start the ignition. The important bit is the immobiliser chip in the keyfob. To replace this, program it and get the immobiliser to accept it requires software. For earlier cars it may work but after 2007, all immobiliser chips have to be programmed via VW HQ in Germany. Similar to programming the clocks for mileage.
In all honesty, if he could make another key for you, do you not think he could then make a copy of yours? He could then have a duplicate, wait till you went home and then stole your car from under your nose.
And because you had the keys, insurance wouldn't payout.