You're right. Where is it being used? It could be a criteria line from a query. An expression like this:
Like "[A-F]*"
will give you all strings beginning with the letters A through F.
I'm not sure what Like "[18]*" is supposed to give though. I tried it on a numeric field and it returned everything. I then tried it on a string field and it returned everything that began with the numbers 1-8. Strange, because I'd expect
Like "[1-8]*"
to do that.
Anybody have other ideas?