Having to get your storage character on, get the item over to your main char, and gettting the existing piece of triple 40 EQ back to the storage char is a lot more visible then going into a vault depositing one item and withdrawing another (because you don't want to ever have 3 items on you, it can be picked up.)
As for tracking, yes that is true but there are lots of ways people can get triple 40 items in excess of 2 for one char, including buying the, picking them up when someone gets fed up and drops all their stuff, hacking a char and a few bugs people have exploited in the past, and in fact folks have been caught doing exactly that.
Bottom line is using vaults would make it far easier then the whole hassles of using storage chars, and is far less detectable. If you have a character who has good enough EQ that you would want to vault your quintx50 light or triple 40 EQ because you have other EQ that is so much better, I'm sure you can afford the rent.
