I keep seeing "free reign" all over Mumsnet and in an increasing number of other places. Including a book on toddler behaviour that I got from the library the other day.
Why don't people know that it's "free rein" as in giving a horse its head? Do people make the same mistake when saying "rein check" and use "reign check" instead?
I don't know why it bugs me so much!
(And it's probably been done to death on pedant's corner anyway...)