Except that bikes are more likely to rear end cars, than the reverse.Perfect. They are doing their job then. Not only did you notice them but you also took steps to get in front of them so the bike cannot be rear ended by you. Pretty much the best case scenario for the rider (assuming you pass safely).
The other thing is that people who start by paying attention, and get distracted while stopped, may see your brake light going out as you starting to proceed. Since bikes tend to outpace cars, when well driven. They may be overenthusiastic on the gas pedal.