Well, I didn't say it was impossible, but challenging. A normal player isn't likely to be doing a ton of building on day 1 and is likely to spend part of the day looking for food (eggs), doing initial quests, finding a good spot to have a base, maybe doing a quest or two, etc. And mining and tree cutting are often not in the same area, so heat is split between them. I think most people aren't going to do significant mining or tree cutting in the first day anyhow because they'll want better tools first... at least a few quality levels instead of Q1, though that's just my assumption.
I think that in a case where a player is doing something unusual compared to the normal way of playing, it isn't unexpected to see unusual results such as screamers. That isn't necessarily something the game needs to account for. There are far too many factors that come into play that can impact how the game plays just based on how an individual chooses to play the game. Some end up being beneficial and some are detrimental. But trying to account for every possible result of every possible way people play the game is a bit too much to ask for, imo. Expect that if you play noticeably different from what is expected that you'll get unexpected results and just adjust your gameplay to account for those results. In the case of screamers on day 1, if that happens, then just be sure you're putting up spikes around the area where you're working. If you're doing that much building, it shouldn't be difficult to do that.
Though, unless it has changed in 1.1, I've done a ton of building with 2 players doing it at once in 1.0 and it took until after the first horde night on 2 hour days before I saw any screamers. We weren't mining or cutting trees at the base, though. Maybe that is why we didn't see any. Heat was spread out in areas for mining, tree cutting, and base building (we built a base that was about the size of the land claim).
