About damping off.
The primary reason for it happening NOT too much water.It has to do with certain pathogens that are in the seed starting mix.There are several of them and here's some links to look at.
https://www.google.com/search?q=damp...&bih=790&dpr=1
And here's a link to one of the links in the above link.
http://www.mnn.com/your-home/organic...id-damping-off
And here's what damping off looks like
https://www.google.com/search?hl=en&...k1.Rzvy8XUkl3A
Summary?
Yes,there are several reasons for damping off BUT it cannot occur unless one or more of the fungal pathogens is present in the seed starting mix.
One of my tomato pathology monographs shows it happening when the seedlings are even 4-6 inches tall.So they can look OK at first, and then down they go.
Carolyn