The risk/reward is much higher.

For the risk category.

The risk is you intrude on someone like the original commentator, an adult and mature person isolating themselves who would feel that even though their time was ruined by your presence they would feel to bad personally to reveal that fact to you by asking you to leave.

But ignoring that anecdote it is a very very very safe assumption that a person alone in a non public environment is there voluntarily and by choice and your entering into an interaction with them is very much not welcome.

It's not a guarantee, but it's certainly overwhelmingly more likely.

I would also argue your "friendships being borderline priceless" is more extreme than any example ever discussed in this entire thread and equally unlikely to result no matter the individuals disposition.

You're certainly welcome to gamble for that but expecting it is naive imo.