If I leave the generator on auto...and power goes out...it doesn't kick in immediately. There's usually a couple of minutes pause at the transfer switch for that exact reason, because many times you get those short, one minute or less outages.
Then when the transfer switch senses no power for a couple of minutes or so...it goes on for a 1-2 minute warm up, and then finally the transfer switch kicks it over. When power comes back on, again, the switch waits for a couple of minutes or so, to make sure it's on...then it switches back to the utility company power.
That's also why I leave it on manual, and when the power goes out, I'll even wait a little longer. I may even call the utility company, since they'll give the expected down time...before I decide to turn on the generator.
If it's daylight, I can live without power for a bit...no big deal.
I also wouldn't want it automatically firing the generator when I'm not home...kinda pointless.