Originally Posted by hopcar
"You can feel the pressure building in your lungs as you rise and you automatically exhale."
I agree with you, it's a danger but not a big one.
Please understand that I'm not just speculating about a theoretical risk. The dangers of lung damage due to breath holding are very well understood and are taught and re-taught during all training having to do with underwater breathing (scuba, surface supplies, etc.)
The Divers Alert Network
reported about 60 cases of lung damage from over expansion in 2008 (the last year I could find a report for.)
From my own experience holding my breath from the surface (so no danger of lung damage,) I feel quite a bit of pressure just from swimming, working (scraping the prop, for example,) and just using up my oxygen. Think about that "bursting" feeling you have at the end of a long breath hold while swimming. I'm not at all convinced that I'd notice a dangerous pressure change before it's too late. Those 60 people in 2008 probably didn't either.