Well, obviously they will known when you receive your funds for your project, else you will be tax avading if you don't report it.
Obviously if you are in need of a significant crowdfunding campaign you'll probably have to relocate to a friendlier place in the EU, at least temporarily (I guess if you are looking for more than 1M euros it might be worth it).
I don't think they care about the backers.
If crowdfunding was like purchase of shares (which it isn't), then it wouldn't be taxable initially, but would have a capital gains tax when you sell those shares.
Most of the crowdfunding projects are in essence similar to preorders, and thus would be taxable as any other sales - if there are true donation projects, then they'd need to file for nonprofit status to be able to get tax-exempt donations.
This is why accountants are important. They know the system and paperwork and words; they know how you can pay tax in one form cheaper and later instead of expensive and now.
I don't think UK taxes lottery winnings.
though UK lottery winnings will still be taken into account for inheritance tax if the winner dies within 7 years.
I don't know about Spain but here it is essentially a need for people in charge of the "digital economy" to somehow feel useful and show that they are "regulating" something. In this case they must feel more justified because it circumvents traditional actors (i.e. banks) and involves money.
It is kind of amusing because this is a sector where most EU countries enjoyed a more liberal regulatory context before startups started to spawn in the US. And now that there is a boom, regulations are added to prevent it from developing, effectively removing any possible european competition to US companies in the space.
I don't know if this will affect the likes of Kickstarter though, if they don't have any physical presence in Spain I don't see how the government is going to know about it.