Interesting - whilst I loathe idiots who use the phone whilst driving surely their company cannot fire them for doing so (unless they are during works hours doing work stuff in works vehicle etc.) as what they do in their own time is pretty much up to them.
Yes, it's illegal, but it's not for the firm to enforce the law in their own way. They could, I suppose, have a policy of not employing people with unclean licenses (not that the Police would prosecute them to give them points anyway as we all know they don't stop them in the first place) but I would assume this would only be legal if they had a job driving professionally.