Is it time to start calling out bad cyclists?

What I had neglected to consider is that even if there's nobody directly behind you, if you slow down with a view to coming to a stop, the gap between yourself and any following traffic becomes much smaller, in short order.

After this incident, my decisions are as follows:

1. Follow the lead of both TTM and Temp and make more use of hand signals when slowing and stopping, in the hope that following riders will understand it from context
   
2. Look harder before doing anything
   
3. Possibly slow down sooner if road conditions permit so as not to take anybody by surprise further along the road (I thought I was slowing smoothly and in good time but the evidence here suggests otherwise)