This was maybe 5-6 years ago, but I use the same password on 10+ accounts. All of those accounts where limited without posting 1 thing.
Today, the accounts that I still use, they're not very many, I dont sell full time any more, are all different.
What kind of a question is that, of course they link passwords.
Think about it, someone with 10 stores is more likely to use the same password so they don't forget. Change the passwords guys, ebay are not as dumb as they used to be.