system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does eBay prevent people from bidding up their own items with a different account?

I mean I could imagine that a friend and I both have eBay accounts.  Hypothetically, I'll put an item up for bid with no reserve.  If it doesn't get to the price point I want to sell it at, I'll have my friend bid it up to that point, or if it still doesn't get there, then he'll buy it and just give it back to me.  

I can imagine a network of people doing this. Two people was just an example, and I could see that if one person sells something then relists the exact same thing a week later they'd know something is up.  Or if two people kept relisting the same item back and forth they'd suspect something.  But are there networks of like 10+ people who could get past eBay's people?
gpt
They don't care, because they take a cut of the transaction. If he buys something for £20 off you, you only get £19 and £1 goes to eBay.


Knock yourself out and do it as often as you want, you will run out of money before they get bored.