My favorite quoting problem is competing quotes.
Why can't you handle quoting properly?
Why can=38#39;t you handle quoting properly=63
Why can=38#39\;t you handle quoting properly=63
"Why can=38#39\\;t you handle quoting properly=63"
"Why can=38#39&%92%92;t you handle quoting properly=63"
\"\;Why can=38\#39\&%%92\;t you handle quoting properly=63\"\;
Followed by people who sanitize strings with a flamethrower.
quot;Why can=38#39%%92;t you handle quoting properly=63quot;
Or just throw out everything after the first metacharacter.
quot