Lady was training for her very first parachute jump, but what she asked the instructor is a doozy

On the first day of training for parachute jumping, a blonde among the group listened intently to the instructor. 

“Alright everyone, remember, when you get to about 300 feet from the ground, you should start to prepare for landing.” 

The blonde asked, “How am I supposed to know when I’m at 300 feet?”

“That’s a good question,” the instructor replied. “Here's a useful tip: When you get to 300 feet, you can recognize the faces of people on the ground.”

After pondering his answer, she asked, “What happens if there’s no one there I know?”