SYDNEY, Oct 5 (Reuters) - An Australian couple got a fright when they were swallowed by a three-meter (10-foot) sinkhole as they sat in their car enjoying the Adelaide views. The couple, who suffered minor bruising, climbed out of the sunken vehicle on Tuesday and found refuge with a resident in the suburb of Glen Osmond. "They were quite shocked, so we gave them a cup of tea and you know, sort of settled them down," Dewald Behrens told the Seven Network. The sinkhole opened above an old lead and silver mine shaft, media said.

Based on that paragraph can we conclude that this sentence is true?
The couple had been careful of sinkholes.
It's impossible to say