Less accountability if the lisence plate is illegible. They may not even have registration or insurance if they are intentionally obscuring their plate.

Failing to signal is a common problem, many cops will use that as a good reason to initiate a traffic stop and determine soberity. Drive behind a BMW for 10 minutes and you'll realize certain drivers use it only 1/1000, rather than they sometimes forget.

For bulbs most cops are reasonable and will write you a dated warning, if you get pulled over again 2 weeks later with the same burnt out bulb, then you're likely to get a ticket.