Hi Jim,
The stopwatch is not used to clock in/out resources. Each resource that is assigned to a particular task can use the stopwatch to report their time for that task. So if there are multiple resources assigned to one task each could use the stopwatch to report their time. If this is your use case then it would be a good idea to set your task reporting policy to 'individual'. You can access this setting by being logged into your account and clicking this link.
Thanks-ps