Given how airlines can make you cough up as much as $150 each way to fly with your bike, S&S-coupled bikes make sense for those who enjoy touring internationally. The initial investment can pay off in as little as three international trips.

The dilemma you present applies to both folding and S&S-coupled bikes. In regard to S&S bikes, my proposed solution is to buy the S&S soft "Backpack" case when you purchase your S&S-coupled bike. Before the start of your tour, remove the semi-rigid perimeter panels and fold the case and strap the whole thing to the top of your rear rack. You could also pack into into a pannier. It's a bit bulky and weighs about 8 lb., so you'll need to decide if it's worth carrying. Since it's collapsible, shipping it by post within Europe is a great alternative. For instance, you can ship it from Switzerland to your hotel in The Netherlands. It will be there within 2-3 days.