But what about a room environment, where it is supposed to have very low moisture levels (no matter if it is winter or summer, cause in the first case you have the radiator heating the room and in the second... it's summer ;) ?

Unfortunately, room environment never has zero humidity, especially, if your summer is as wet as mine, here...

It's a question of statistics. If the air in the bag you put the chip back again would be totally dry, then not much bad will happen. But if the bag was filled with air of room environment, then situation looks different. Then, moisture has a better chance to penetrate the chip, and an oven heating is recommended.

Keep in mind, that we talk here about highest level of reliability. Most people will never see a failure due to moisture having penetrated chip package, I guess.

By the way: Thanks for the nice champion-ship pictures...

Kai