Should obese people have to pay for two seats on a flight?

Many airlines have policies and regulations for this. Should you not be able to be seated with both armrests down, not excessively encroaching on other pengers' personal space, and wear the seatbelt with no more than one extension, you can have a single seat. Should you violate one or more of those requirements, you'll need to purchase a separate seat. Should the obese be penalized financially for their size? Well, should other pengers be penalized because the penger next to them is obese? Should the airline be penalized financially because of a penger's weight? I weight 140lbs. An obese penger can easily weigh 300 lbs. That's double my weight. Pengers get charged excess weight fees on their checked-baggage weighing over 50lbs. Shouldn't the airlines have seats that cater for all shapes and sizes? Well, most carriers have first class, or premium economy seating with more legroom, and possibly greater seat width. Unless you want to distribute the cost of these "extra room" seats to ALL passengers, effectively increasing EVERYONE'S airfare, which are only allocated to certain passengers, you'll need to charge passengers that use them more.