And proof checkers doesn't replace mathematicians. But the existence of proof checkers puts (a subset of) mathematics into the software realm.
I feel that it is probably inevitable that at some point we will have computer assisted legal analysis.
Here's a speech of his touching on this very topic from the '80s.
http://www.michaelkirby.com.au/images/stories/speeches/1980s...
For example, if a lawyer knows which arguments have the highest probability of success, she can focus on framing the facts of her case in the way that best supports those arguments. A system that does this would not replace lawyers - but would assist them in some very important tasks - and would be a big step forward.
I also believe these technologies are inevitable, and (plug) at http://www.judicata.com we are working to make that vision a reality.