When you consider that planes have crashed killing all on board due to overloading, it's actually a pretty big deal. http://www.nytimes.com/2003/05/18/us/crash

When you consider that planes have crashed killing all on board due to overloading, it's actually a pretty big deal. http://www.nytimes.com/2003/05/18/us/crash-that-killed-21-appears-tied-excess-weight-maintenance-error-officials-say.html http://www.nytimes.com/2003/05/18/us/crash-that-killed-21-ap... http://www.detroitnews.com/story/news/local/michigan/2015/11/28/ntsb-case-western-plane-overweight-crash/76516092/ http://www.detroitnews.com/story/news/local/michigan/2015/11... http://www.bbc.co.uk/news/uk-scotland-glasgow-west-32732607 http://www.bbc.co.uk/news/uk-scotland-glasgow-west-32732607 https://sputniknews.com/latam/201612261049016624-plane-brazil-colombia-crash/ https://sputniknews.com/latam/201612261049016624-plane-brazi... https://generalaviationnews.com/2011/07/18/overweight-airplane-crashes-2/ https://generalaviationnews.com/2011/07/18/overweight-airpla... http://www.dailystar.com.lb/News/Lebanon-News/2004/Mar-29/291-crashed-uta-plane-carried-10-ton-overload.ashx http://www.dailystar.com.lb/News/Lebanon-News/2004/Mar-29/29... Google tells me that the average person weighs 80.7kg, let's conservatively round up to 100kg to take into account clothes, and luggage (It's probably higher). From this we can estimate that the PIA flight had an extra 700kg (It's probably closer to 1 tonne) of weight on board, and extra 700kg that wasn't properly secured or distributed. Depending on the plane, the effects could range from using up more fuel (planes carry extra fuel for emergencies and so they can circle their destination while they wait to land, it would eat into this reserve making flight incidents more deadly), to failing to take off the runway; The pilot wasn't informed until he was in the air. While the plane in question is certainly larger and more powerful than the majority of the links I provided, the fact of the matter is an overloaded bus or train may refuse to move if overloaded, a plane can fall from the sky killing people both on-board and on the ground. Planes fail deadly. You now have 7 extra, fragile humans standing in the aisle who have nowhere to belt down in case of emergency. If the plane crashes, needs to make an emergency landing, or even encounters incredibly rough turbulence they could be thrown around the cabin hurting both themselves and others. As for a 1 to 10 scale of transgression, it's hard to place because of the nature of such a simplistic scale. Assuming your scale is confined to aeronautics (lest we invoke Godwin's Law) what counts as a 1, and what counts as a 10? If your 1 to 10 scale is truly inclusive of every possible aeronautical incident then 1 has to be a passenger with a typo on their ticket, and 10 has to be 911. I don't know about you, but I have no idea where to place this overloading incident on such a scale.