If you're referring to me tagging FM, I only tag when I'm in their area. As for a Boundless tag, I tell my guildies we don't use tags or anything of that nature because we recruit based on friendships and friendliness. We don't recruit based on pro-ness, high damage, merch ability, or anything like that. They are free to tag what they wish but we don't have a specific tag that we're required to use.
It's good to have guild pride, and we do, but showing it off too much can give people big heads sometimes. Boundless keeps a low profile and just doesn't want to start drama.