Wouldn't it be dangerous? For players, I mean.
Of course.
That's the main thing on my mind, how many people will die if this became popular. And if there would be stories of people stealing phones of people, after they got hit by a train. In order to steal their tokens.
Its only as dangerous as the user makes it. Users will need to agree to terms and services stating it is the end users responsibility to play safe.
Take a look at Pokèmon Go, it has millions of players and here is the deaths/injuries from a game with such a following:
http://pokemongodeathtracker.com/(BTW we are not comparing ourselves to Pokèmon Go)
The users GPS is never shared / stored on the servers and you cannot see other players in the game. Terminals are placed around the map randomly using mathematic equations so you cannot sit and wait for a user to come along and ambush them.
If a phone was stolen they wouldn't be able to change the withdraw wallet either without security measures we are implementing.
I didn't mean it to sound like a criticism. I just meant it as a factor of percentage. A small percentage of people are such that they are not careful. Or a small percentage of people will eventually get into accidents.