(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.