Depends on what you class as an OOB.
Its been a long time since I built a kit with just what's in the box. I'll at least change the markings if I'm doing an A/C kit. Doing the same plane as everybody else did, just kinda bugs me, I guess. But, that might be ALL I do. As others have said, the new kits really don't need much AM stuff. And when you really can't see it, why bother. If that still counts as an OOB build, OK, I do them.
Now when building a ship, I'm going for PE railings, scratchbuild mods, just about anything.
It may be just me, but building a OOB aircraft carrier, slapping a given numbered decal on it and then calling it the USS Whatever is just wrong. But then, unlike planes, no two ships are often just alike. They all have differences, changes over the ship's life, etc. Representing those differences is what makes modeling ships challenging for me. But again, that's really the nature of a ship model.
Of course, everybody's free to do models the way they want to. Just keep it fun.
Mike