This was my worst fear about a year ago. Worrying that someone was going to pull me out of line and ask me to buy two seats.

It doesn't seem like a very practical system but it doesn't necessarily seem unfair either.

Paying per pound (assuming you AND your baggage would be weighed) seems more reasonable to me than arbitrarily deciding that some people need to pay for two seats whether or not they can fit into the seats provided (Some people are quite heavy, but carry all their weight in such a way that it doesn't flow into the seat(s) next to them. For example if you have protruding breasts, stomach or butt, but aren't any wider than an average person, you wouldn't need that extra seat, but you'd be charged for it any way, because of your weight).

Also the combined weight of a person AND their luggage makes perfect sense to me, because it directly relates to the fuel needed for travel, so it actually seems (to me), fairer than any other system. Babies and small children would no longer fly free, even if they didn't require their own seat, but if you were paying for a family flight by the pound (again including luggage) you could compensate by carrying less luggage.

You also wouldn't even have to weight folks or their luggage separately, in fact, if you were traveling with a family or group, the entire group could be weighed together. And it's not like anyone else would have to be allowed to see or hear your weight. And if other aspects of the flight were itemized, the person behind you would need a calculator and the complete fee schedule to calculate your weight.

Maybe the idea doesn't bother me, because I do not have a problem with my weight, especially the "number." Writing it on my forehead in ink, wouldn't bother me. I'm fat, and anyone with eyes can SEE that, it makes no sense whatsoever to me that the actual number, would ever be considered more important than what can be seen just by looking at me.

In absolute terms it makes sense. In the real world, however, this would never fly (excuse the pun). If a US carrier tried to do this they'd have their pants sued off of them, regardless of whether it was a sensible way to load the plane or not!

Also this ^^

What do they do? I have never seen anyone be weighed before boarding...?

Southwest Airlines Customer of Size Policy

"Customers who encroach upon any part of the neighboring seat(s) may proactively purchase the needed number of seats prior to travel in order to ensure the additional seat(s) is available. The armrest is considered to be the definitive boundary between seats; width between the armrests measures 17 inches. The purchase of additional seats serves as a notification to Southwest of a special seating need, and allows us to adequately plan for the number of seats that will be occupied on the aircraft. In turn, this helps to ensure we can accommodate all Customers on the flight/aircraft for which they purchased a ticket and avoid asking Customers to relinquish their seats for an unplanned accommodation. Most importantly, it ensures that all Customers onboard have access to safe and comfortable seating. You may contact us for a refund of the cost of additional seating after travel. Customers of size who prefer not to purchase an additional seat in advance have the option of purchasing just one seat and then discussing their seating needs with the Customer Service Agent at their departure gate. If it is determined that a second (or third) seat is needed, they will be accommodated with a complimentary additional seat(s). "

I wish we could go to an airport and test out the size of a standard seat and seatbelt. I guess there isn't a whole lot of need for it but I really want to see if I can fit now or if I will be continuing to hug the window side so I never touch the person next to me. My husband always takes the middle, he's a sweetie (and a thin one at that!).