I’m of a split mind here.
On the one hand, to me being stuck on a stationary aircraft whose climate control systems can’t keep up (not unusual for an airplane relying on the APU and not the main engines in flight) is a horrible situation. At some point, just let the poor people off back into the damn terminal!
On the other hand, I can’t really condone some rando walking on the wind. Some parts of the wing can take it, but others *WILL* be damaged by someone walking on them, requiring inspection and a replacement aircraft.
So I guess, yeah: opening the emergency exit for some damn air after hours of being trapped in an oven is something I can sympathize with, or even approve of. But walking on the wing just caused further (necessary from a safety standpoint) delays.
There was an incident several years ago where an AA headed to DFW landed at Austin(?) because of bad weather in Dallas. AA would not let passengers off the plane, even those that final destination was Austin. One passenger stated they could see their car in the parking lot from the plane. The pilot came on the intercom asking passengers to stop calling 911 saying they’re being held against their will.