Join Mumsnet "for free"- anyone's teeth set on edge ?

[charlieandlola]

Come on MNHQ, please make this banner grammatically correct.

I am going to report this post so you can get Tech on the case . Think of it as a free Christmas present for us pedantic people.
Thank you

[IceTheChristmasKateMumsnet]

@charlieandlola

Come on MNHQ, please make this banner grammatically correct.

I am going to report this post so you can get Tech on the case . Think of it as a free Christmas present for us pedantic people.
Thank you

Oh go on, you can flame me to high heaven.....why is it wrong? Is it because the "for" bit implies you have to give us something, but "free" indicate you don't have to pay anything?