She presumably meant an "alternative " route – that is, a route that offers another option, rather than one that should be taken on every second occasion that the journey is undertaken.
Making the same error, Sky Sport insisted for some months on offering viewers an "alternate" commentary on rugby matches, instead of what was presumably an alternative commentary in Maori. And I was depressed to see a road sign over Christmas offering me and other drivers an "alternate route".
The confusion between "alternate" and "alternative", and the use of one when the other is meant, are now well-entrenched in American English – and, sadly, the mere fact that the two words are now so often misused means that we have now, through sheer laziness and ignorance, ruined two perfectly good and useful words.
Nor is this the only instance of such a corruption of our language. What I take to be another Americanism – the use of "substantive" (referring to the substance of an issue or process, as opposed to the procedure or detail) as an up-to-date alternative to "substantial" (meaning of substance as opposed to slight or minimal) – is rapidly gaining ground.
The Americans, of course, have, as they say, "form" in such matters. They have for some time refused to use "lie" to mean recline, and use instead the transitive verb "lay" which means to place something (like an egg) down.
The Americans are not responsible for every misuse of the language. Take, for instance, a home-grown usage that is now constantly heard, particularly but no longer exclusively, in the mouths of young people. People of whatever age who would never dream of saying "me went to town", rather than "I went to town", are apparently persuaded that by adding another subject to the sentence, the usual rule is supplanted, so that we constantly hear formulations such as "me and Tom went to town".
Does any of this matter? I would argue that it does. Those demonstrating a lack of regard for our language and careless as to its correct use tell everyone forced to listen that they are people who don't care about getting it (or anything else) right.
We enjoy the immense privilege of using our language, with all its richness and complexity, as our native tongue. The rest of the world increasingly uses English as their preferred medium of communication, but we native speakers can enjoy not only its utility but its beauty as well.
We should not only be aware of our good fortune but also understand the responsibility we have to the language. To speak it carelessly or ignorantly, so as to confuse meanings and corrupt its functioning, is the equivalent of hitting bum notes when playing a great piece of music.
We all have the opportunity of striving to use it as well as we can – but those whose business is language, in that they speak it or write for a living, have a special responsibility - and congratulations to Simon Dallow for reminding us of that.