I did some research and I definitely see the problem:
Meanwhile, a conservation sign tells tourists the real story:
I particularly love the part that emphasises that if they nick your stuff that's squarely your fault for letting them. Wikipedia (where I found these pictures) draws a clear line between human and kea behaviour:
"Kea parrots have strong cognitive abilities. According to recent studies, kea have a sense of impulse control and forward planning. Kea can wait up to 160 seconds for a more preferred reward. In addition, kea also use trial-and-error tactics and use observational learning to solve difficult problems and when faced with puzzles and locks. These decision-making abilities are similar to primates and other intelligent bird species such as the African grey parrot."
"The Department of Conservation suggested that the time savings resulting from a human-assisted, more calorie-rich diet gives kea more free time to investigate and damage things at campsites and car parks."