It appears that the Copy/Paste function in the attribute window overwrites fields that are set to read only. I had an editor copy/paste attributes from one polygon to many and the fields that were set to read only were overwritten.
Has anyone else notice this? Shouldn't a field be read only if you set it to read only in the Layer Properties? Is this a bug?
This looks like a bug. A field does stay read-only if you try to paste into that one cell. However, if you use Paste Attributes to paste all of them, it will update the read-only field. We'll look at fixing this in an upcoming service pack.