I liberally play on both side, and I am talking about the glitch not faction changing
I think you misread what LordKotaro said. Kotaro is not suggesting you faction change.
What you need to do is to create a separate account specifically for transferring goods from one faction to another.
This account will only ever have one toon on it at a time. That toon will only be level 1 and either be light or dark depending on where you are transferring goods from or to.
If you are transferring from light to dark you would create a light toon, then put the goods into the warehouse for that toon (along with enough gold/silver/copper bars that you can afford to get the goods out again).
You would then delete the light toon. This takes you to the faction selection screen where you would select the dark side.
Create a dark toon, go to your warehouse and retrieve the goods you want to transfer - all done safely and securely.
Note: If you prefer, you don't need to create an entirely new account, you can just use a different server to your normal one - the crucial thing is that there should be no toons on the toon selection screen.