The key to accurate forecasting and precise reporting is the “Estimate to Complete” column on the Progress Report. The team members don't have to report that they are behind; you (and most likely, your team leaders) need to make sure that they come up with an accurate estimate to complete, and the math will tell you the rest. How do you know if their estimate is accurate? Unless you (or your team leader) are involved in the details of the task, and understand the technology used to perform it, you won't – the first time.
But the next time, you will know the team member’s bias –
unbridled optimism (forecasting too little),
gloomy pessimism (forecasting way too much) or
random don’t-have-a-clueism (forecasting erratically)
– so you can “guide” them to a better estimate and then hold them accountable for it.
The thing to remember is, you can't just take what you’re given. You have to question the estimate to complete, you have to compare it with other tasks, and you have to get it to the point where all of you are comfortable with it.