To contractors/self-employed PCB designers - what CAD program do clients want?

[nctnico]

If it is a small company they might not care that much and care more about costs and the final pcb functions like it should, which is why I would be very reluctant to do this kind of business in the first place, so much can go wrong with EMC and layout and who's to blame?

I deal with EMC (or better said: CE compliance) in a very simple way: I tell customers I try to design with CE compliance in mind but there is no guarantee a design will pas without an actual (expensive) test. So if customers want to have their product tested for CE compliance they can get that but it costs them extra money for testing and making the changes.