I wouldn't assume that there's no difference for someone who is older, uneducated, or unemployed, because the cross-border friction is WAY higher for them. You

I wouldn't assume that there's no difference for someone who is older, uneducated, or unemployed, because the cross-border friction is WAY higher for them. You might be right, but I don't think you can simply assume it. For example, a well-educated, professionally employed person old enough to have an established family is highly immobile for those very reasons. Their jobs and their family ties are holding them in place. Who knows how these factors all net out.