Eddie does not disable anything, however "Network Lock" feature flushes any iptables rule and writes new rules to prevent traffic leaks outside the VPN tunnel. The previous rules are saved and restored when Network Lock is disabled or Eddie exits normally.
Should OpenVPN or Eddie crash, Network Lock rules will of course remain enforced preventing traffic leaks. In such a case, in order to restore the older system rules, you will need to re-run Eddie and close it properly.
As a long time user of AirVpn (many usernames over the years) and Eddie I can confirm that out in the "wild" this works as Staff says. I keep UFW set to everything blocked, even LAN, so that no user on my machines can go online without being in an Air tunnel. When you close Eddie the UFW rules are placed back in play. Works flawlessly!!