I can't reveal more about my volunteering, but I will say that it was never me who made the calls, it was always a supervisor who could monitor the conversation.
But asking permission is not really an option, and I'll explain why using a different situation. We were also mandatory reporters, which meant that if we knew that a child was being abused, we had to report it to the authorities. This was actually a very high bar to climb, but once we knew it, we had a duty to report. It was a threshold after which it wasn't our decision.
The way it worked with suicidal folks was that they had a risk assessment, and only folks who were both at high risk and were unwilling to work with us to come up with a strategy for staying alive would be at risk for a call.
The "working with" is critical. We weren't looking for "turn your life around" moments, just "Can we keep you alive tonight?" kind of plans. This meant that if someone told us that their plan for the night was to smoke a ton of pot and sleep... while we couldn't condone illegal activity (depending on where they lived), if it kept them alive for the night, it was what we went with.
There was a lot of watching Netflix/Youtube/Tiktok until the person fell asleep- and that was alright with us.
The only people who had emergency services called would be folks where they'd say to us "I'm not willing to come up with a plan" and or "I'm not going to be safe tonight" and when we'd tell them that we'd need to call emergency services unless they told us they'd be safe, still didn't do that.
Like I said, this was very rare, about one in a thousand people.