This is politically incorrect but ultimately logical. I pay now to check an overnight bag (which I used to be able to carry-on), but some 500 pound person can get a middle seat and make two people miserable.
There's an airline that flies to some pacific island that has an obesity problem and they weigh the passengers and charge them appropriately. This should be a standard operating procedure on all airlines if they wish to continue to reduce the side of passenger seating.
You're wrong about that part... it's not logical.
That is a purely emotional response born out of ignorance thinking that you won't be affected and it's only the obvious fatties that will suffer (which pleases you).
First off, if you don't fit in the seat (with the seatbelt around you) you can legally be deplaned.
Secondly, it won't work that way. Airlines, particularly low cost airlines will just end up using it as an additional revenue stream by setting the baseline absurdly low, such as declaring the average human to be 40 KG. Also it's going to be fit people who will get hit by it (muscle weighs more than fat, so Mr I'm only 0.000000000000000000002% body fat will be heavy). The heavyweighht boxing class starts at 86KG and they're not exactly giants (speed is more important than strength or mass in boxing but that's going widely off topic).
Thirdly, performing and enforcing this isn't going to be free. As mentioned, the roided up body builder is not going to like being lumped in with the fatties you want to laugh at, let alone the powerfully built company director. Airlines will have to employ extra staff, pay for the facilities and the security due to people getting aggro at the fact they're heavier than they think and have to pay an extra fee. So it's a huge increase in costs which means it's going to cost way more than it saves. Which means for your moment of schadenfreude the price you'll pay for the ticket will go up.
So you think you'll be immune to it, but in reality it will be used as a cudgel to charge you more (well everybody, but I doubt you thought of or are concerned with that).
There's an airline that flies to some pacific island that has an obesity problem and they weigh the passengers
Erm no. this is not because they want to reduce passenger seating, it's because the planes they use for island hopping literally have a low weight limit. A DHC6 100 (popular for these kind of routes) has a seating capacity of 20 and a payload of 960 KG... That's 48 KG per person for 20 people. Airlines doing island hops are already having to lower seat counts because they literally can't carry that many people. Small planes have a small MTOW... the M stands for Maximum (Take Off Weight).
I pay now to check an overnight bag (which I used to be able to carry-on)
Oh dear, you can't carry on your massive oversized case and take up the overhead bin room meant for the entire row any more... Diddums.
This is one of the things that are likely to change in the near future. Too many people are abusing the carry on limits and it's costing airlines. Not in weight but in time, it's taking longer and longer to board a plane because too many people spend too much time trying to find places to store their 18 oversized carry on bags. Cabin crew are having to spend time moving bags around all of which which delays pushback. I see a few things happening.
1. More airlines will start offering a checked bag included with a standard ticket.
2. More enforcement of carry on limits.
3. Plastic/fabric dividers in overhead bins so that oversized bags literally don't fit any more.
4. Any bag you want to put into an overhead bin will have to be checked and tagged (with your name and PNR on it). Airlines tried doing it the other around by tagging bags to go underseat and found that the tags were being discarded before boarding.
And I know some of you, particularly those who abuse the carry on system because you don't want to check a bag will complain... you've only got yourselves to blame.
If I'm going for more than a few days (meaning more than I can fit in my 30L backpack) I'll get a checked bag because it's just not worth lugging half a ton around an airport when I can just drop it off at the first stop.