Malicious actors? That relies on there being malicious actors physically near you, which isn't necessarily a valid assumption. Set up a DMZ, try it, and see.
(B) Having your computers spuriously seized for a police investigation is a risk shared by every computer user, but those investigations cost money. They don't tend to seize your hardware frivolously, except to intimidate (fairly common for security researchers, for some reason). If you have a public Wi-Fi network, and there's no reason to believe you're a culprit, they're more likely to ask you to keep MAC address logs, or shut down the public Wi-Fi network, than assume you dunnit and try to prosecute with insufficient evidence. You're at far more risk running a Tor exit node than a public Wi-Fi network, and most Tor exit nodes don't get raided by the police.
Your neighbours are probably not cybercriminals. It's probably okay to be nice to them.
Not where i live. We have layers of rules specifically designed to prevent random actions by police.
Yes, the risk is quite low, but it's a risk shared by any occupant of an INTERPOL member state.
WiFi isn't some sort of aether, it is created.
Earned? WTF logic is that? I pay for the water I drink. What in the world are you on about?
No, I don't think I will. I will continue to keep my wifi password protected so that randoms can't degrade my Internet speed by torrenting movies 24/7, send death threats to public officials from my IP address, or engage in other unsavory activities.
Not sure why you are equating a natural resource like air with a paid service like Internet connectivity, but it comes off as bizarre and naive at best.
some ppl view "internet service" similar as access to drinking water, which some countries have legal obligations for and the public sentiment would be very much against you if you deny it to any stranger.
some countries/ppl not so much