Would you trust a seed swap seed?

Its February, so it must be seed swap time again!
Seed swaps have been growing in popularity for some years now. The best known one in Britain is Brighton’s Seedy Sunday. The events are an excuse for a get-together for gardeners apart from anything else, and since gardening often is a rather solitary activity, this seems a jolly good idea. Very often the seed swap is just a peg on which to hang the event, with most attention and energy spent on going to talks, eating, networking, buying stuff from stalls etc.
But what about the idea of the seed swap itself?
Basically the idea is that you save seed from a good variety and then package it up and offer it to other people, so you are sharing your good variety. But why do this when the range of seed available commercially is so good?
Promotors of seed swaps like to portray themselves as keepers of genetic diversity, safeguarding old varieties from extinction and keeping that diversity going for the next generation. Commercial seed producers are generally cast as agents of wicked corporations which are trying to limit the range of what we grow, so they can monopolise it. Particular venom is reserved for F1 seed varieties, which will not breed true and are therefore ‘one use only’.
Seed swaps tend to concentrate on vegetable varieties. Given that such an epic range of vegetable seed is now available commercially, whereas the range of ornamentals: annuals, perennials etc, has actually gone into decline, I would be more likely to see myself visiting a seed swap to get interesting ornamental varieties. The emphasis, and the undoubted moral ardour is however very much on the veg, so that is what I’ll concentrate on.
Sorry to pour cold water on what sounds like such a good idea, but I’d be pretty wary about getting my seed from a seed swap myself. Here’s why.
Is it what is says on the packet?
With the best will in the world, it is very easy to muddle seed up. I have just been informed by a correspondent that DEFRA (the British government department for agriculture and the environment) recently did a survey of online seed sources, and 60% was the wrong species, i.e. not just another variety of carrot, but beetroot instead!
How has it been kept?
When you buy a packet of commercially-produced seed, you can be 100% sure it has been harvested and stored in optimum conditions. You can never be sure with seed swap seed, where its been. Seeds deteriorate if conditions aren’t right. Damp shed? Overheated room? This season’s harvest, or last years?