SmartStasis.

It calculates based on drop rate, calculates out what the chance is of a drop happening, and if all drops have reached/passed 100%, it stops trying to boost drop percentage... In a similar way, if drop rate is 0%, due to either base level or by lowering the drop percentage, it won't run the boost, as it's not worth it.
Edit: Anyways, the way the internal mafia code works, it goes straight off the percentage for 'normal' drops... as it stood, unspaded items were 'normal' items with a 0% drop chance. That's what meant they were unspaded. Because of that, they were never valid items, unless specifically a condition. Spaded allows for choosing how we want to handle pickpocketting, while allowing drop rate guesses to be in, and us to know that the drop rate isn't finalized... but might be that.
System runs like this, all in Persistence/MonsterDatabase:
shouldSteal runs, checks if dodge is likely and if so if the monster has any items that should be stealable using shouldSteal(monster.items) to check, if dodge is not likely it checks if any items would satisfy conditions and be stealable using shouldSteal(conditions).
shouldSteal(items) checks what your drop modifier is, then compares each items to see if it's stealable using shouldStealItem(item, dropmodifier).
shouldStealItem(item, dropmodifier) checks if the item is an item (false if not), then checks for specific overrides... pickpocket items are always yes; nonpickpocket, conditional, and bounty are always no. currently spaded items are in the same category as NCB items, but shouldn't be. then, if not caught by those exception categories, it checks against the drop rate modifier to see if the item is guaranteed to drop based on drop modifier, and rejects the pickpocket if it's guaranteed.
next, if the monster doesn't drop the item, it checks the items that the monster drops to see if maybe one of them is an ingredient for the item being compared. it compares each ingredient to shouldStealItem(item, dropmodifier) to see if it's a possibility. if any of those returns true, it returns true for the whole function.
then, as it doesn't drop the item requested or any ingredient desired, it decides that this item isn't worth trying to auto-steal on.
Am I getting this confused? I looked through this whole system several times trying to figure this out and tracing out why it was doing this. The solution seems easy... it's just a question of what's the best result, whether we want this to always pickpocket or work based on item drop multipliers. As it stood before, it would always try to pickpocket, regardless of how high you may get your item drop percentage, or if it's even possible. 0*drop multiplier or anything else will always be < 100, and evaluate as true...