And if I am going to respawn in time then I can just hit the undo button a bunch. The rules clearly state that doing such isn't prohibited. If you receive punishment for that then a support ticket and a Rioter looking at the game would clearly show that there are no grounds for punishment. A view of the game isn't even necessary as the online match recording system can clearly show the time at which each item was bought, and it is easy to prove that the time of your death overlaps the end of the game, and it was only after your death that you bought 6 tears.
Playing with such a build can be considered to fall under a number of different rules, but the items themselves are not grounds for a punishment.
As it stands I do it for the laughs it gets out of people. If Riot sees me selling my items and buying joke items beyond the point where items are useful for winning the game (AKA death) and punishes me then a support ticket would quickly clear such a thing up. You might say not to risk it, but the fact is that I am perfectly willing to risk having an account go through processing for the opportunity to make some people laugh, which it does do.
Heck, I may have spent more money on my LoL account than most things I own, but if I am not willing to risk having that be permanently banned over a misunderstanding for the opportunity to add a few extra laughs into the lives of strangers then I wouldn't be happy with who I am.
As it stands though there are no grounds for punishing people for switching over to 6 tears when you are dead and the game is about to end so long as, if you do come back up in time, you refund your items.