Maybe there's something in the higher valued items that the mechanics of the chute can scan that the shitty 5 chyen immy clothing does *not* have?
Also, considering that the chute give a tiny percentage, and the amount the immy clothing gives would be less than 1 chy, round that down (favor goes to the city) and voila. ;)
Why would the city make it easier for someone to make money when they can?
[Also, RL experience:
A can recycling machine in California. 5 cents for every 2 cans. (2.5 cents each, not bad, not great.)
But if you only put in 1 can, you get 2 cents.
The chute reminds me of that machine to some degree.]