I'll add something to strip out those unexpected characters to prevent this particular case but there are certainly risks of making the site inaccessible by putting something incorrect there and I can't prevent that completely, it is documented. If any small typo or mistake is made the site will become inaccessible. That is why this setting is disabled and hidden by default from Web.config, it is only meant for use by those who understand what it is and what it does and who are prepared to fix it in the database if something goes wrong.

Best,

Joe