Is It Safe to Have Caves/Shipwrecks/Logs in the Tank?

[Vaughan06]

I have been avoiding putting caves and logs in my aquariums lately due to the risk of my Bettas drowning in them.

I was under the impression that if they decide to rest inside, then when they need to go up for air they won't be able to.

Is this a reasonable fear? Or are Bettas smart enough to wake up and find their way to the surface?

[Purple]

Every living thing has the will to survive, and will do anything to do that. They won't drown themselves. If they were that stupid, they would have died out by now. How do you think that whales who sleep at the bottom of the ocean come up to air? It is perfectly safe as long at the holes are big enough for the fish to get in easily, or small enough that they can't get in. Also, make sure that it is aquarium safe.