No sense agonizing over it, Beanz, just plan to ride and have fun. That's about the root of your question, isn't it?
I pretty much always ride solo. The hard part is when others log these beautiful times! When I read "did a double in 12 hrs" I need to realize that they were in a paceline with some guys named ullrich, spumoni and allegro. Even when I get passed, I have some crazy ethic that says I can only draft 'em for a minute. Sure, all I have to do is say something nice and could I jump on this train? But generally I only do that in bad traffic or safety-in-numbers situations. I guess I just don't want to put up with it - call me lazy, untrained or scaredycat but it's easier and more carefree when not drafting. Wouldn't it suck to get in a wreck from drafting a stupid rider? Wouldn't you be the stupid one for being behind Klutz? Why do you think that space was open?
I find that organized doubles are a little less brazen than what you describe. The riders are more experienced, but they're more tired and conserving harder so it kind of ends up the same as your average century. The easiest way to change the dynamic? Swerve! Learned that from a semi driver. Only takes one easy swoosh and they realize they're in the wrong place. Or I'll wave 'em by and say "I've got 100 miles to go, I'd hate to start swerving on you." Doesn't really make sense but that S word says a lot.
I'd feel lucky to find a rider to team up with, who likes similar pace, similar distance, generally shows up, etc. It hasn't happened yet. I'm often the friendliest person out there, have no problem making friends but doubles are a different animal - fast riders aren't with my long-haul pace and hurting riders stop all the time. Frankly, most riders I know don't want to be there when it gets tough - hot training rides or hilly courses or long training days seem to promote yard-work and honey-doos. That's OK too, I sometimes need support drivers! There's also a class of rider who can ride a strong century, but aren't trained up for a double. The only way they'll make it is in pacelines. That's a safety hazard, man, don't bring 'em