Save Error Output
Since the using the clipboard isn't on the table, it would seem wise to offer a different way for Lovers to get the exact text of a blue screen without having to open up a text editor and type it themselves line by line.
A possibility would be to offer saving at the end of the error message- something along the lines of
"Press S to save this message to " .. love.filesystem.getSaveDirectory() .. "/error.txt"
That way they can save the error, open it up, and get help without having to retype a lengthy error message.