[iainmerrick]

people don't say "I'm going to Burger King's" or "I'm going to Costa's"

Oh yes they do!

There's nothing to analyze: "Tesco's" is just wrong.

It’s kind of funny that there are prescriptivists on both sides here, all convinced that they’re right.

[TylerE]

In 40 years I have no seen such usage in print

[iainmerrick]

People say it.

[b112]

You may not be wrong that people do say it, I'm sure people say pretty much anything, across this vast planet. Yet people use double negatives, when meaning the negative too. Doesn't make it right.

[iainmerrick]

I think language is defined by real-world usage, not by the logical structure that we theorise underpins it. If so, double negatives actually are right, or at least they can be, if they successfully communicate meaning.

[brianmcc]

You're not wrong.