Departing USA

Hi My sister has overstayed her i-94 3 month VWP visa in the US. She really didnt intent to do so initially but got a job, loved the weather and etc. etc.
Now, 3 years later (!) she is planning to return home to Ireland for good. No I expect that she will be barred from etnering for 10 years and can never use the VWP again.

My question is, does she have to worry about getting out of the US. Will she be pulled aside at the airport and given a stern talking to, or could she be detained for days. I have heard about some scare stories.
Thanks for any advise

I didn't know they check immigration status when you leave the US? They never checked my visa. All you do is submit I-94 to airline officer (if you have one) (not immigration official). I could be wrong though! Wait for experts.

IIRC no one is going to stop you departing unless there are certain criminal proceedings in place and your name is on a 'no fly' type list. Airline staff during check in will collect departure portion of her I94W and transmit info to CBP. Where a passenger has 'conveniently' lost their I94W a form exists to record pertinent data from your passport that can be/is cross referenced with their previous entry. In any case where there are no exit records the burden of proof is on you to demonstrate your timely departure when you next seek admission into the US. A question I typically ask in these cases - was the ban worth it?