Boundary Conditions

Tesco is to change the wording at it's checkouts.

"10 items or less" becomes "Up to 10 items".

The reason is that one should say "10 items or fewer", but some people are not sure.

The nice thing about the old wording, from a software engineer's point of view, is that it provies a clear specification. It uses wording that (despite the English faux pas) has a well defined mathematical meaning.

Unfortunately, they are going from the frying pan into the fire with the ambiguous specification of "Up to 10". Does that mean the the maximum number of items is 9 or 10? Up to 10, or up to and including 10?

I don't think I've ever bought fewer than 11 items in a supermarket, and I don't foresee me generating test cases for the boundary condition.