It's a "50/50" situation we're talking about here. Yes, having mines spawn in T1 POI's, remnants included, would be sketchy because a lot of new players (from what I assume at least) start doing T1 quests before they are ready to "take on the rest of the world". However, there is no magical barrier blocks entry to other higher tier POI's until you're x gamestage, so a new player, or a new character even, could easily walk into a T3 POI, make their way through a couple rooms, and then die to a sneaky landmine trap.
My general conclusion is this: perhaps dogs should be able to spawn in certain T1 POI's on day one (the ones that are hardcoded to spawn those vicious canines), but only if they are hardcoded not to detect you until you get relatively close to them (or you attack them), and/or the animal should be exposed so that it's impossible to miss it.