Creatures should only be pickpocketable, if they have been called from other existing places, where they live naturally.
If summoning in ADOM means - CREATION of the creature from living matter then of course its pockets should be empty. Otherwise summoning = "calling for help" so creatures teleport in from other places of the world and are existing persons with Social Security numbers and as such - taxable by IRS - so very pickpocketable.
ADOM Creator should decide: are summons real persons/monstersons or summoned creatures are just XEROX copies of a race - for example the gremlin?
In the special case of gremlins, where they replicate via water - they should be unpickpocketable, because this counts as replication - xerox copying the creature - so they cannot have had lives collecting their loot, just popped into existence.
In the case of other summons Thomas ought to decide:
Summoned beings no longer can be picked. The logic here being that it leaves open the question if summoning actually retrieves the monsters from some other place or creates them temporarily. Yes, this thus also affects treasure drops...
This decision makes summoning a creation. Possibly then all creatures to be summoned exist in an infinite number as holographic blueprints on a remote plane of existence, from where they can be called into being and animated. Like in vitro clones or like people on Star Treks Holodeck.