I noticed after renaming a BOD book Garbage\ that the backslash would insert a </font> at the end of the name. So I renamed the book <basefont color=red>G\ and it applied the </font> which caused the title in the bod to turn red.
This is actually intended behavior. There is actually some very low level HTML tagging going on in some of the gumps ingame. So when you use that character it can break that section of the display, but otherwise cause no other issues. Ill take a look at sanitizing the input for "/"/"><" in the future.