Deleting a connected meeting should not delete the task.
It does not

or at least should not...
This process caused two issues.
1) I deleted a connected meeting from a task.
Just what I wanted. However, it then deleted the task. Bad news
I checked code : there is not code doing such thing.
I also check test case : the task is not deleted, only the link between task and meeting (task cannot refer any more to non exiting meeting)
Which version are you running ?
2) the deleted task id was then reused
Possible, but only if it was the most recent activity (last id)
and linked all existing requirements, tickets to it. This is causing confusion.
Really strange : deleting the activity would have deleted all links to it.
In the attachment the sequence of events was:
1) I deleted a meeting #64 from task 16646 on Friday 02/01/2013 15:56:47 and in the same instant it deleted the task 16646 without my authorization.
2) on Monday 02/04/2013 09:14:22 another user added a task and it selected the deleted task id 16646
3) the confusion started as all linked requirements to the original task 16646, etc were then displayed against the "new" TASK.
Could you reproduce this ? (I could not...)
Which version are you running ? Did you change anything in the code ?