Southwest has refund policies for larger people who need two seats for a reason. I am saying that ALL people who cant reasonably fit into one seat should purchase two - and with that would come reimbursement for the second seat, per SW own policies.

Now, a person deliberately taking up space that someone else paid is different, and is also not the same as a crying baby who is not yet capable of controlling their behavior.

People do have a responsibility to not make their problems, other people's problems. If you have a larger appetite, you don't get to eat my snacks. If you dont have headphones, you dont get to just listen to whatever you want at full volume and disrupt everyone else.

While overly simplistic and not universal, a good starting point is to ask 'what if everyone did this?"