Mining Bitcoin? Unlikely since only pool know your IP.
Running Bitcoin node? More likely since your IP will be known to other node and appear on crawler website such as
https://bitnodes.io/.
Never mind this newbie-like question. Some people's location are unknown, are they those that uses Tor or VPN? If using Tor, you can set it to a country address, the countries the Tor is set to will be displayed to the country set to? This later is how I thought it would be, but how come some location are unknown.
You could use VPN for your node but it's waste of money unless you already have some unlimited vpn plan, so good alternative is Tor that is already free.
Tor is not only fee, it is decentralized, unlike VPN that is centralized, people that route their connection through VPN depends on a centralized server that knows about their IP addresses. If people can run their own node using Tor, I do not see a need to go for VPN at all.