Card insert dupe?

Originally posted by [b]SomeServerAdmin[/b]
http://www.eathena.ws/board/index.php?autocom=bugtracker&showbug=2585

The "Main Gauche" story strikes again.

------------------
[t0] - [charid] Bought on vending 4140 (Abysmal Knight Card)

[t0+2min] - [charid] Dropped Main Gauche[3] with 4140,0,0,0
[t0+2min 1sec] - [charid] PickedUp Main Gauche[3] with 4140,0,0,0

[t0+10min] - [charid] Dropped Main Gauche[3] with 4140,4140,0,0
[t0+10min 2 sec] - [charid] PickedUp Main Gauche[3] with 4140,4140,0,0

[t0+13min] - [charid] Dropped Main Gauche[3] with 4140,4140,4140,0
[t0+13min2sec] - [charid] Dropped Main Gauche[3] with 4140,4140,4140,0
[t0+13min4sec] - [charid] Dropped Main Gauche[3] with 4140,4140,4140,0
[t0+13min6sec] - [charid] PickedUp Main Gauche[3] with 4140,4140,4140,0
[t0+13min8sec] - [charid] PickedUp Main Gauche[3] with 4140,4140,4140,0
[t0+13min10sec] - [charid] PickedUp Main Gauche[3] with 4140,4140,4140,0
-----------------

Nice dupe without relogging, etc. That was whitesmith, though I don't think it matters, since there were no cart transactions.

My assumptions:
He dropped items to check if it worked. The problem lies within card insert code.

for(i=0;i<sd->inventory_data[idx_equip]->slot;i++){
if( sd->status.inventory[idx_equip].card[i] == 0)
{ //Free slot found.
sd->status.inventory[idx_equip].card[i] = cardid;
clif_insert_card(sd,idx_equip,idx_card,0);
pc_delitem(sd,idx_card,1,1);
return 0;
}
}

what if pc_delitem(sd,idx_card,1,1); cant delete the card? Though we got massive checks above and I cant find out a way to exploit the system...

B> Ideas, leave offers in private.