My employer doesn’t discriminate against minorities, women, the aged, but if your work history shows you were in a union, you’re not going to get hired.
When I went back to school, I got to help choose my replacement before leaving the small company I worked for. One idiot had the gall to include "Union Organizer" on his resume. We called him just to see if he would come in, but he was a no-show for his appointment.