Somone just sent me this at the airport lol

While I do agree that it's annoying on trains, buses, etc., this does look like an airport. So it's taken out of context. For all we know, their flight was delayed for 4 hours or something. And you can also just ask to move their bags. I feel like this woman-spreading, man-spreading stuff has gotten out of hand.

I'd just pick up her bag and shove it on the floor.

I travel a LOT and if someone is trying to do something like this at a busy terminal where there are more people than seats I can almost guarantee you airport staff will ask/tell them to remove their belongings from the seats. This is assuming multiple people standing nearby dont do it first. This photo is zoomed in though and there isnt any real context--this specific terminal could be almost empty or have very few people around, in which case go for it sister relax. When I've been on red-eye flights with almost no one at the terminal I'm waiting at I'll lay down and take a nap.