I kinda like it. To me it seems like effective guerrilla marketing or something Banksy would do. I think it actually spreads a good message and would definitely pique people's interest. Whether it's illegal or not shouldn't matter as you're very unlikely to get caught anyway and fuck tha police.
Surely a cheap and effective way of promotion. But I remember there was a discussion about it on reddit, many bitcoiners didn't like it at all, saying it's kind of cheap and intrusive. It could be pretty irritating to see your banknote polluted with unwanted advertisement. So the effect could be opposite to intended, instead of people going to a website to learn about it, you could get: "I don't know what Bitcoin is but I already don't like it".
I think the negatives would outweigh the positives. I think it would adequately spread the message of bitcoin and it's all for free.
Somebody please organize sales of stampers and tell us where to buy them!!! You could make a shit ton of Bitcoin if you started selling these next week. I'd buy one today!!!
Just make a stencil yourself and print it on to some card the spray paint the bills. Simples.
