I am having the same issue. So many dots really clutter up the map and don't show what is really important, where they are now. The demo "Redlands Incidents" shows only the last location of the emergency vehicles so it would seem that the capability is possible. Also, it would be nice to be able to label each collector location so that you would know who is who on the map instead of feature: 0.
I would also like to know how they did that. Does it need tracking analyst for server or something?