How would one effectively use "Mnemonic Siphon" spell?

[Atracious]

I was looking at this spell but, I can't see it actually being useful.

It states "The rune remains dormant until the object finds its way into the hands of a spellcaster" Which means that the spellcaster would have to hold the object, and I don't see how one would get them to hold an object that is actively stealing their spells.

[avr]

Perhaps it's an item they won't want to lose (their main weapon, the king's crown etc.), could be they can't easily determine what the item was (one of the coins in the big bag you just used to pay them; it doesn't say it has to be touching them, just in their hands), maybe they're your prisoner already, or you might just accept that you're only going to get one spell off the target.

For that matter the second function just works when the object is in the creature's possession. Sleight of hand sneakiness, enchant a tanglefoot bag, etc.