[arrowsmith]

This is not true. We don't apply this "rule" to any other establishment, e.g. people don't say "I'm going to Burger King's" or "I'm going to Costa's".

There's nothing to analyze: "Tesco's" is just wrong. It's not the name of the business.

[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.

[euroderf]

Interesting observation ! Might it be because Tesco and Costa resemble ordinary names, and therefore easily appear in a possessive form ?

Or it might be about imaginary hierarchy. There could only be one actual duly-anointed king of burgers, but if one were to use the definite article to mark this, saying "I am going to the Burger King's", it would imply firstly that the king of burgers does actually exist, and possibly also secondly that he has but one solitary burger outlet.

A grammatical construction not quite so jarring when used with (say) "Tesco".

[swores]

Pasting my reply to someone else rather than rewrite the same thinking:

I agree it's not consistent, but who ever accused English of being that?! My point isn't that all business names are treated that way, just that the ones that are the reason is grammatical tradition not (for the most part) people who incorrectly think the shop is called "Tesco's" or whatever.

(But as others have replied to you, it's also more common than just Tesco, definitely including "Costa's" for lots of people.)

[d1sxeyes]

Costa’s I for sure have heard. Burger King’s I agree though.

[Affric]

lol… I am glad for you that you haven’t heard those yet.