It's a case of the wrong bag for the occasion. Rucksacks are for hiking about the countryside. You pack it with provisions and only need to take it off your back for lunch and when you set up camp again in the evening.QUOTE]
Nay, nay, nay!
When I'm off up-country (or to that fetid metropolis otherwise known as 'London') for a couple of days or longer it makes sense to put everything I'll need for sleeping and so on in a rucksack, while storing more regularly needed items in a little rucksack or holdall. You won't get very far attempting to last through the Climate Camp or the Big Green Gathering with only the contents of a mere manbag, I can tell you.
And, should I accidentally ruin someone's day by bumping them over on the tube, I can always make my rural accent sound extra-rural and do the country bumpkin act by way of apologising instead of having to set fire to them with my cigarette lighter or bayonet them with my camping cutlery set.
Win-win all round, methinks.