Haha.
Unfortunately, people do that all the times. Lots of people do that after each update for instance. They should not. I explain they should not. They do.
For anyone to notice such "BC Break" they would have to:
- Be stupid enough to purge all URLs
- Happen to use the article title instead of alias to generate URLs
- Happen to have an article with a | character in the title
- Notice or care that that URL is generated differently the next time it's generated by sh404sef after the purged URLs (which I don't think they will ever notice or care, given that they're purging URLs in the first place, means they have no idea what they're doing)
So I don't think you will ever have a single complain for this if you strip it by default :D
So honestly I would just strip it by default and call it a day. (which sounds the fastest solution)
Or this (but this sounds complicated):
I think I'll try to add a specific syntax for characters to exclude such as \| as you said, or just a double ||
Or even:
Ignore it and forget it, it's such a minor issue :D