This remind me initial war with Gmail on trying to change colors of links in your HTML email body. Google was replacing #000000 with blue links to make sure so

This remind me initial war with Gmail on trying to change colors of links in your HTML email body. Google was replacing #000000 with blue links to make sure some won't deceive users that underscored black text is or is not a link. So of course people start using #000001 color, then this one got blocked they went into #000002. Gmail quickly realized they wont win this one :) so they revert it back to replacing only 000000.