Rowan, are you saying because I've never pulled a fully loaded trailer behind a kids tricycle, I cannot approximate the sensibility of that experience? Calling fixie utility is a stretch and if it makes sense depends if the rider wants to put in the extra energy riding a fixie takes (i.e. also has a non-utility agenda like personal fitness). Most everyone else, I'm reasonably sure, are quite content to coast down the next hill after working so hard to get up it, and want some gears to choose from so they don't blow their knees out climbing it, and want standard brakes so they don't waste energy trying to stop (or get injured trying).
Fixie is for fitness, that does not mean an individual cannot use it for utility, but not reccomended in the general case. Is this a hard concept or something?!?
Absolutely on your first question. Unless you have, then you don't know what it might be like. You can try to put your own collective experiences together to try to imagine what it's like. But until you actually do ride a kid's trike iwth a fully-loaded trailer (whatever that is supposed to mean), then that's all it is... your imagination at work.
Most people can coast downhill to their heart's content. I don't care. They are free to do what they like. For the record, coasting downhill after a hard climb is not really the best thing; ghost pedalling will help clear the lactic acid from the muscles and avoid cramping. But obviously there is no place for physiology in utility cycling.
And another for the record (having just returned from my 50km round-trip shopping expedition on my fixed gear), my bike is street legal because it is fitted with not one (as required) but two brakes. Don't brand everyone who rides fixed gear with the same reactionary tarbrush you apparently like to wield in suggesting we all ride without brakes and use our legs to stop.
And another for the record... my knees are in superb knick, despite (a) the fact I ride fixed a fair bit, (b) I ride a lot of hills and (c) I ride loaded for touring and utility purposes.
And just who is or is not entitled to make recommendations on whether someone can use a fixie for utility purposes. No-one said I could or couldn't ride a fixed gear; I make my own decisions, thank you. And I am sure the OP will, even if he tries it just as something to to make him competent to make comment and to satisfy his mechanical bent.
Just as an aside, there is another issue not related to "frozen" freewheels, and that's cabling. In winter, it does become an issue as it becomes clogged with ice and gunge (of course, if you ride in those conditions). And back on freewheels, the viscosity of the oil used to lubricate the bearings and pawls inside it does become an issue in temperatures well below freezing... as does the viscosity of the oil used on the chain that can affect shifting performance. THIS comes from someone who lives and rides in conditions down to -40 deg C. So a fixed gear can go some way to mitigating some of these issues.
Like your style, Sixty-Fiver! Just goes to show... utility doesn't mean you have to be feral.