in the same topic in DM question, thrawn said:

People would go invis or stealth and steal any loot.

take some drows with heat vision beasts. send an illithid salve in a disguise, or any other good idea to trick the poor adventurers. get them not prepared, and take all the loot back (put an importent object, for IG reason to recollect it)

for the low lvl, im sure, we can find something proper for them.

i suggest a dm-free-of-scripts-mostly quest contest! :D

-If- Its possible to solve the invisible cheating, why not just give the monsters all perma - see invis, If its possible.

heh, to give them some chance, then catch them, encumbered

We have various tools to prevent this, it's mostly an issue that it's kind of a pain to take the time to set something up and then have it never be found.