UKH

Is a roll top rucksack like this https://www.amazon.co.uk/Lomo-Dry-Walking-Roll-Rucksack/dp/B00E8JFS9W/ref=s... any good for dropping things into without removing it from your back? I ask because it is now possible to shop in Sainsbury's (and probably other supermarkets) by scanning your items on your phone as you go round. So you need one hand for the item, one for your phone, and you could just drop each item over your back into a rucksack. Then, when you're done, you just have to pay, close up the rucksack, and off you go. Given that I cycle to and from the supermarket,  the idea is very appealing. Or would I risk just dropping things on the floor by failing to place them in the rucksack?

Maybe even one of these https://www.vidaxl.co.uk/e/vidaxl-firewood-backpack-with-carrying-belts-44.... would do the trick!

I like to take care with how I pack my bag when shopping; can't see just dropping stuff in would work for me.

Yes it sounds like a good way to crush your plums.

Yes, that's true. Fruit is at the entrance of the store so would tend to end up at the bottom. And sometimes they request a rescan to make sure you're not stealing anything. Handing over some crushed fruit to be rescanned wouldn't be too great.

I would drop everything if I did that.

A shame this appears not to have worked out https://www.kickstarter.com/projects/wolffepack/wolffepack-modula?ref=proje...

That's harnesses, not rucksacks...

Isn't it easier just to put the rucksack in a trolley and pack it properly as you go? 

Otherwise stuff would fall out if you bend down for something on a bottom shelf?

So you used to wear a Whillans too .....

I think that probably is the best solution, yes. Although at my local supermarket the trolleys do tend to be jammed together where they are stored, and hard to extricate.

Depending how much you buy and how much you care about banging stuff up a cycle couriers bag with the secondary step could work.

Get a cargo bike or a trailer and use a normal shopping bag?

Wear it backwards. You'll look like a tool, and probably trip over things, but it'll work.