Ohhhhmg!!!
This is so dumb but so good cuz it should also over-rule the stupid shop-switch trick!
LOL!
Let me explain:
When in market, some ppls with multis like to hog shops for their other acct's (well I do it too).
I mean they set up shop with no items to sell, then later their other acc't logs in...
So you're camping / waiting for hours to get a shop in a good spot for yourself, but no...
Cauz now their other acc't comes in and blocks the FLAG (not the shop, but the FLAG)...
And now their shop-hog acc't quits and you can NOT get the shop cauz the flag is blocked.
But they can cuz blockers can still access.
And if u think u can go to edge of screen until flag is there but not them, I wish u good luck cuz your char will never run to shop in time to set up before they do.
Maybe not anymore

Put on peace mode and wait for the flag blocker - A SURE sign someone is switching shops LOL.
As SOON as they quit, click and setup > Likely you will be faster cuz it takes a sec to switch screens on a multi (even if it's just a 2-acct'er).
Will have to try this.