According to this article in the Daily Mail, a British company called Carphone Warehouse is not accepting business from people over 70 unless they are accompanied by a younger family member.  From the article:

The 75-year-old would only be allowed to sign the forms for the
Carphone Warehouse’s TalkTalk phone and broadband package if she was
accompanied by a younger member of her family who could explain the
small print to her.

Mrs Greening-Jackson, who sits on the board of several charities, said:
"I was absolutely furious. The young man said, ‘Sorry, you’re over 70.
It’s company policy. We don’t sign anyone up who is over 70.’

And later:

When her case came to light on Radio 4’s You And Yours last week, Carphone Warehouse admitted it had adopted an over-70 rule.

But the firm insisted it was not a blanket policy and claimed the
guidance was to protect the elderly. A spokeswoman said: "It is not our
policy to refuse business from adult customers of any age group.
However, we do ask our agents to use their discretion when dealing with
older customers."

She added that the discretionary rule had been introduced in response to complaints that staff had mis-sold products last year.

Now if what she says is true, that they put a discretionary policy in place to try and prevent someone who’s clearly not right in the head from entering a contract, then I can kind of understand their motivation.  My question for them, though, is how did you figure 70 is the right age, and why in the world didn’t you just make it a blanket policy for all ages?  After all, I’m fairly certain they see their share of young people who aren’t right in the head and need to be protected from entering into binding contracts.  All you need to do is look in Parliament there, or Congress here.