Why don't cops ticket driving with no lights on? Or those who don't realize they are driving with daytime lights at night? Or with headlights or taillamps out? Or driving with high beams towards oncoming? Or inappropriately aimed headlights? Or my other pet peeve, signalling before looking (like how bus drivers now change lanes - but they are much more careful about doing this now)?
These are all obvious, clear indications of driving without undue care and attention. By nailing these infractions, it would generate steady revenue and make it clear to the offenders that they should have some consideration for others on the road.