Any low value physical transaction doesn't require any confirmations.
Yes they do. Ask any merchant if those "low value" transactions need confirmation. Many companies rely on those "low value" transactions so they want to be damn sure they take place.
It would be *extremely* difficult to pull off a double spend, and would simply not be worth even trying for a low value transaction.
So why does Mt Gox and everybody else wait at least 10mins and normaly 30mins even for "low value" transactions.