Well I doubt I was drunk.
But I have been thinking through this quite a bit. There is a possibility I ran a rogue miner binary around the time of this transaction. I was experimenting with mining alt coins at the time which is actually why I became interested in PTS in the first place. I vaguely remember downloading a quark miner which I was immediately suspicious of. I cannot find any link, and I have already erased any trace of that software from my machine.
Fortunately all BTC/LTC wallets I have are cold and/or encrypted.
To be honest I had not thought anyone would take an interest in stealing altcoin wallets, but I may indeed have been wrong. This is the reason I had not gone to the trouble to encrypt the wallet, and obviously that is a mistake.
Ah well... it embarrassing, but it is not the only time in life I have made a mistake.
I wish this community well... my assume PTS have vanished into the hands of a dishonest person.
I am deleting all altcoin wallets and old empty BTC and LTC pub/private keys from this machine (so i don't erroneously use them) and moving on.
Lesson learned. I suppose my PTS days are over.