This tag marks a variable as not requiring escaping by the template engine,
potentially creating cross-site scripting vulnerabilities, so shouldn't be used
unless absolutely necessary. In these cases, I don't think it's necessary.
Change all links when possible to not mention a site, so HTTPS will be used
automatically for same-site links.
For embedded images, and other links out to the rest of the world, use HTTPS
when the site is known to support it.
