I think any move towards online resumes is great. It makes no sense that all recuitment is online yet all documents are off-line. I don't keep a resume anymore, but on occasion someone asks me for one. I normally tell them I don't have one and point to my site, linkedin page, etc. A couple of times recently I've been told that 'online resumes are not accepted'. Presumably because they can be changed after the fact. I…
Or instead of locking it, you could just have a "Last modified" time stamp or a log indicating when modifications were made.
Another option is that a new revision generates a new random string for the URL and that revision is always available there.