Tickets submitted for a project do not show up as activities, such as in the activity count displayed by each project in the project list. While there is a distinction between planned activities and tickets, it's very possible that a project might have more task activity via tickets than in the plan. It would be extremely helpful to have the quantity of open tickets reflect on the project's status some how.
Also, this might be a bit much, but I'm afraid of people closing projects with tickets left open because the ticket count isn't shown anywhere except under the tickets tab...
-Mike