All they will need to do is remove cap and reinstall proper ones.
It is just ugly probably will not leak.
Does this mean that ridge cap shingles are mainly cosmetic rather than functional? I'm not familiar with their purpose. If they're just cosmetic, then maybe I won't worry about them too much. We did just have a super-heavy rainstorm and the garage didn't leak. If that storm we had didn't make it leak, nothing will. At least for now.
Yes a row of shingles is overlapped front to back to seal. The cap just helps hold all in place.
Sometimes a roofer will wait a while (years in some cases I know) to put on a cap on his house.
At least until the wife points it out. U tube
Look at the ends in video that is how it is done with no vent.