The tickets themselves have no info on the magnetic strip except the ticket's serial number. All info on how many days the ticket has left, when it was used, and the biometric finger scan info, is all saved on the WDW computer system. Because of this, the only way to check a ticket is through a place that has direct access to that computer system.
Since the Disney Stores don't have such access, you can't check hoppers (or upgrade or modify them, or anything) at the
Disney Store.
Disney doesn't have a phone number to check them for 2 reasons: 1) it would cost money, and 2) they want to keep down on the second-hand ticket market. After all, only a fool would buy a ticket he couldn't verify was still good, right?
Even the WDW resorts didn't have the ability to check tickets until sometime in 2005 when they got a computer upgrade, because the resorts use one computer system and the parks use another, and the connections between the two are somewhat basic.
Basically, the only places you can check your tickets are:
1) Guest Relations at the theme parks
2) Ticket sales windows at the theme parks
3) Guest Relations desks at Downtown Disney (there are two)
4) Guest Relations at the WDW resorts (NOT Swan and Dolphin or any of the DTD hotels)