Considering that the status quo is currently that literally asking the individual and querying the source of truth to confirm the history of an individual directly for the purpose of discrimination are ubiquitous practices... yes, I think such laws would be very effective in reducing discrimination on the basis of criminal and judicial history.

If we have not even said that it is wrong, then it's going to happen. Saying that it is wrong and should stop happening is the first incremental step in reducing its rate of occurrence.