I understand that you are speaking from the experience of someone who works for an airline, but please understand that I am speaking from the experience of a frequent traveler. I appreciate you pointing out that the rules for carry-ons are likely going to be different on an international carrier, and OP should definitely check on the rules before committing to this plan of action, but I think you're being unnecessarily confrontational with all this talk of "torment" and your assumptions that anyone who goes carry-on only goes unprepared for their trip.
Last fall I went to WDW on a 7 day trip using only carry-on (two backpacks, actually; one a regular size that goes under the seat, one a lightweight backpacking pack). After packing 9 days' worth of outfits (I like to be prepared), all my toiletries and first aid supplies, my iPad, sunglasses, paperwork, park bag, extra shoes (I had a total of three pairs of walking shoes including the ones I wore on the plane, plus flip-flops for the pool), swimsuit, chargers -- basically everything except oversize liquids -- I actually had a comfortable amount of space left over in each bag. I bought several souvenirs and had no trouble bringing them home. I will grant you that 12 days is about the longest I'd do without a checked bag if I did not plan to do laundry (actually not that onerous if you're going to have a resort day or two, which is a good idea on a trip that long anyway), but that's all I'll grant you.
I'm really confused by this argument and I think you've misunderstood the premise. The duffel bag isn't there to be "snuck on"; if one ends up needing the extra bag on the way home, one checks the extra bag. I'm also confused by why you're arguing that "Bag checking is a pain and expensive" after spending so much time trying to convince everyone that checking a bag is the only way to travel.
Yeah, you're right, it
is a pain and it
is expensive. The duffel bag option is just recognizing the fact that it may be necessary after shopping in the park.
Ah, this one is actually a good point, and should be addressed. The way to deal with this problem is to go with an airline that allows you to pick your seat ahead of time. Pick a seat that boards relatively early, even if it means you'll be near the back of the plane and have to wait a little longer to get back off. The earlier of a boarding group you're in, the better your chances are of getting an overhead bin -- and when you arrive at the plane, don't be shy about putting your bag in a bin several rows (or even half a plane if you didn't get a good boarding group) away your actual seat. Again, as someone who's been going carry-on only for the last decade, I've done this and not had trouble getting my larger carry-on on the plane.
Okay, once again I'm confused by your argument. This sounds more like you're arguing against traveling alone at all?
What does sitting in the middle seat have to do with your carry-on luggage? If you're talking about not having under-seat space, that's solved by being savvy when you pick your seats. Frankly the middle seat issue is solved the same way.
If you're talking about not having legroom once you put your bag under the seat in front of you, there's a solution for that, too. I'm tall for a woman, and I found a way around that issue years ago. The bag has to be under the seat for takeoff and landing, but there's no rule about it staying under there for the full duration of the flight. As soon as we're cruising, I pull my backpack out from under the seat and tuck it close to my own seat, under my knees, so I can put my feet under the seat in front of me and stretch out. Makes it easier to get at my in-flight entertainment, too.
I live in FL & can go to WDW anytime, but the Holy Land is my dream trip.
