Trade Window with non-existent NPC

[Toomuch]

Has anyone else ever been able to open up a trade window with nothing before? This very thing happened to me today.

I was in SolA on my warrior, at zoneline C to SolB, as I was about to go in and level there. I saw there was a high level druid sitting right there in the middle of the circle room/landing, so I asked if I could donate some pp for a natureskin. She said yes, so I got 50pp and opened trade and clicked yes. However, right as I was clicking Yes, I realized it was a single column trade window, the kind with NPC's, and not the 2 sided trade window that you can open with players. The 50pp did indeed go away, but not to the druid. I tried to give her some pp still after I realized that something was buggy, but she said "no thanks" and logged.

I was a little bit baffled, but I actually reproduced the glitch a few times over. It seems that you need to be standing in just the right spot, and you can literally give coins away to nothing, or a non-existent NPC, an NPC's ghost, or whatever you want to call it. Once the trade window is open, you can even add other items. I didn't go through with the trade/giving away of items that I put in the trade window, so I don't need any real reimbursement, but if this is possible to do here, are there any other spots where you can give stuff away to the void?