What hugh just said is generally what follow the ingame mods indeed, although, in theory, if you are able to prove it (which is sometime impossible) here are the rules:
Any account should always be intentionally played to its own benefits. That means sending resources on purpose to another player with no apparent reason is pushing. (or giving villages)
Though, sending ressource as exchanges, as favors for defense or attacks on players or as repays, as exchange between villages or for villages, as trying to avoid being nobled or attacked by another player or for a other ingame favor such as joining a tribe or under a ingame pact is legal. This means, you can almost always avoid being banned for pushing because you could actually not be pushing. It also means mod wont ban you for pushing with the same logic.
Note: Exchanging any ingame ressource, favors, threats, etc for premium points remains Illegal.
Pushing means: you purposely want to boost another player with the sole purpose of advantaging him while harming your account.
The same principle applies to villages. In the case a player gives villages for no apparent reason though, even if it is considered pushing, it wont be considered pushing anymore as the player could have been inactive, absent or noob and wouldn't have noticed him giving villages.
The merging accounts applies to the same logic also, meaning, even if in theory it would be illegal as pushing with villages, ingame, it isn't. An account owner could decide to leave his account and thus, get nobled eventually by another player or go barbarian. Him joining the account nobling his last account does not interfere in the pushing rule at all as you can see. There is only the standard 24 hours wait when changing account on a world and him deleting his old account or, find a way to, in theory, to not know the 2 passwords of 2 valid accounts on the same world. This rule isn't related to the pushing though.
Same logic applies to tribal inactives.
Hope it clarifies :icon_neutral: