DSs (16 & 19) and DD (22) have their locations visible in Snapchat. It was a condition of them having phones/social media when they first got them.
They've chosen never to switch it off (well, DS1 did for a while at 16/17).
DD likes the fact we know where she is - it gives her some comfort. So it's entirely her choice. Plus it's useful for her friends too. We don't actively check.
DS1 spent his first month at uni missing lectures and pissing about. We had a massive intervention, given how much it's costing us to support him with his choice to go to uni. He now likes us to know that he's going to lectures, and sharing his location is the easiest way to do that. So again, largely his choice (though i think we'd probably ask him to share if he switched it off, at least until we are more reassured he's taking uni seriously).
DS2 has never thought to question it. He is mostly at home, or with us anyway, but occasionally he goes out on long bike rides with his mates. He says he prefers us knowing where he is too, in case he falls, or has an issue with his bike (we helped his friend fix his bike when they were out on one of their first rides). So again, mainly his own choice.
On the flip side, they have always had a lot of freedom to do what they want - provided they were happy to share where/who/when etc. We have always been a very open family, and as a result, it's what we're all comfortable with.
If any had a problem or concern with it, we could absolutely have a proper conversation about it, and then decide together how to move forwards.