I had a thought while I was out oppressing marginalised groups (I'm cishet male, it's what I do apparently). What if, by some stroke of fate, a cis person in crisis ends up on the Trans Life Line during one of the rare moments when it's staffed? It could happen, maybe that person googled for help lines and misread the results, people who are suicidal aren't thinking clearly and are doing well if they're even able to ask for help. So what would happen? Would TLL try to help this person even though they weren't in their target group in an act of human fellowship? I doubt it, since they view their mission as political. Would the wayward cis person at least be directed to the regular suicide hotline? Doubtful. They'd probably get yelled at, at the height of their emotional fragility, and hung up on.
EDIT: It's weird how transtrenders talk about cis people like we're a separate species.