>The platforms also face the problem of banning someone only to have them open a new shop an hour later as someone new.

I think Ebay lets you screen buyers based on feedback, i.e. refusing bids from 0-feedback accounts. I could be wrong though. But this is one way to avoid this problem.

It helped for awhile but the obvious methods around it work fine (buy something dirt cheap and get feedback, then scambid later)

Funny thing about the feedback. It helps the buyer more than anything. It became meaningless when you stopped being able to leave negative feedback for the customer. [1]

I remember having a discussion with customer support about this "You mean you will pull money from a sellers account and potentially cause financial harm based on accusations of a person with a 1 feedback when the seller has thousands of positive?" the answer "we cannot rely on feedback alone sir"

I slowly moved away from selling on ebay commercially at that point. Every few years I list a couple items (still have some inventory, or something to sell) only to have someone scam or attempt to scam within weeks. There seems at times the only "gain" the scammer gets is to cause a "loss" to the seller...not sure the end game though.

[1] https://pages.ebay.com/services/forum/sellerprotection.html

They can ban you more thoroughly, based on the delivery address, for instance. A determined scammer can just buy a new PO box, of course.