I believe the escaping happens on the receiving end, since some links do work fine when sent via chat.
The color tags and custom links have been disabled in the past, probably because someone used them for some exploit. When the game launched it was still possible to send colored messages, but it's not something I would like to see again.
Custom links on the other hand would be very useful. Right now I misappropriate a certain [Ancient Scroll] book link for my libAbilityTooltip in order to send custom links that don't look like garbage when seen by players without
sidWarTools, but that's really just a hack.
p.s. some people say you need to sacrifice a goat in order to summon Chip, but I don't believe in that superstition.