[*]I would even advocate that all prospective employers, public and private, be prohibited from asking for, or even seeking, prior arrest status... we as a society either believe in "innocent until proven guilty", or we don't, and a conviction would show up on its own.
I would agree for this in general employment. However, if an individual is to be bonded, be involved in security, medical and child care, and a great many other jobs I think things like criminal record should be known.
If I was to hire an individual to work for my landscaping company, I would want to know if they had a record for burglary. Because they would have ample opportunities to do such crimes again as my employee.
If I was to hire somebody as a clerk in my medical office, I would want to know if they had a record for drug abuse or sales, since they could have easy access to drugs at work.
If I ran a Charles Chubby Pizza Palace and wanted to hire somebody to portray Charles Chubby, I damned sure wanna know if they had a history of sex crimes (especially against children).
Now if I was hiring somebody to deliver Pizza things like this are not so important, because at most they could only take a small amount from the company, and interactions with customers is pretty minimum.
If I was to hire somebody to work sales at an amusement park, I would want to know if they had a theft record. But if they were in the janitorial staff or maintenance staff, I would not really be concerned about this.
With me, such questions should really only be allowed if the crime could be related to the position that they are applying for. Otherwise, it should not be asked at all.