Title says it all!
To be fair, even a 10 or 20 atm watch would likely have fogged up after 5 years of hard wear. A watch's water resistance is all about the gasket integrity... and gaskets start to break down after 2-3 years, particularly if the watch is exposed to the elements. If the gaskets become compromised, then it doesn't matter if the watch was originally rated for 5 atm or 50 atm: It's going to leak.Just a matter of time, but the water resistance will get you. I wore a 5bar Chrono daily for 6 years and and beat on it.
After the 5th year, its fogged up and had to be rebuilt. I wouldn't make it a GADA unless it had at least 10 bar or more, or was a diving chrono with screw down crown.