This is enlightening: bale or bail

Wouldn't "Bale Out" be some sort of harvest-related activity, possibly taking place in WWII and involving steam tractors and Land Girls?

And I thought it would be taking blocks of hay out of the barn.

The phrase finder site is great! It is often a start for my research on the origins of phrases when I write that type of article, and often quoted as the source as many sources are mentioned on the pages.

I was at Liverpool Street station at the weekend, and was mildly shocked (although not, being me, actually offended) to walk past a (shut) kiosk proudly displaying a greetings card with the message "KEEP CALM AND FUCK OFF" to any and all passers by. I suspect that Mary Whitehouse would not have approved...