In case you don't already have it handy, here is an article by Olson that you might want to read through:
The Minnesota Citizen's Personal Protection Act of 2003: History and Commentary
Hamline Journal of Public Law and Policy, Vol. 25, p. 21, 2003
https://papers.ssrn.com/sol3/papers.cfm ... id=2070938Nothing on Humphrey jumps out skimming the first part. It may, however, point you in the right places to look for more information.
ETA:
And there's this, the source you are almost certainly remembering (because there you are in the comments
http://www.freerepublic.com/focus/f-news/938637/posts1991 -- REDEFINING DISCRETION
Beginning slowly, Attorney General Skip Humphrey takes the discretion idea statewide.
He lobbies Twin Cities Metro police chiefs to deny permits requested for personal safety.
He encourages out-state cities to do the same, in the name of "state-wide uniformity."