What safeguarding training do staff get? Railways are incredibly risk averse in some areas but in this department?
Nothing particularly specific but we have general training about how to spot vulnerable individuals. It all really falls upon the personality of the specific member of staff as we aren't shown procedures on what to do in cases with vulnerable people. I (gateline) can't actually authorise travel for someone, but I do try to get someone to allow it (usually a guard). If I think someone's being genuine and they have a problem with their ticket (not necessarily a dead phone), I tend to give them to benefit of the doubt but will warn them that they may be charged for a new ticket or given a penalty.
A lot of people (of any age) come up to me and say "my phone is dead, can I go in to charge it?" and they conveniently have a charging cable but not a wall brick. My station has 3-pin sockets outside the barriers (for cleaning equipment) which can be used for charging phones, but the USB ports are inside.
I think the trouble is that people seem to be a little sociopathic when it comes to getting what they want. I've seen some damn good actors who are pretending to be vulnerable to get free travel, and as soon as they think they are out of vision, the act is immediately dropped. I had a woman ask to charge her phone so I pointed out the sockets outside but she said they looked dangerous and refused to use them (??). She then started shouting saying she was gonna get free travel anyway and she'll push if I don't let her in. Radio for some assistance (obviously it's at the crack of dawn) and then she starts fake blubbing about fleeing domestic abuse. A despicable thing to lie about to get free travel... and yes, she was let through. Supposedly she's a regular who gets violent very easily.
A good, customer focused attitude there, I like it!
I try my best!
It's not difficult at all. "My phone is dead, can you let me through?"
"No, you'll need a ticket"
And then another passenger distracts the staff with an unrelated enquiry before the kid has had a chance to ask "do you know how I might be able to get hold of someone?". The OP did state that the gateline was busy.
As busy as the gateline is, I wouldn't stop my conversation with someone like that. They obviously need help and they obviously can't solve it on their own. A good follow up would be something like "do you have any way to buy another ticket" or "is there someone who can buy you a ticket online". I tend to focus on one person and fully explain/solve their issue before answering anyone else. If the extra 3 minutes of waiting is enough to make someone miss their train because their ticket was rejected by the barrier then, frankly, it's their own fault for leaving it too late. The only times I will walk away from someone to help someone else is if I am having a casual conversation, or I hear a forced paddle alarm. Someone being trapped/potentially injured is more important than which tube line someone needs to take!