Yes bounty campaigns, especially signature campaign which is usually the highest percentage in bounty and some airdrops can make you earn a lot. Always join airdrops because it is easy and it does not need much effort,I new someone who earned his first million through airdrops. But I cannot say that it is safe and not risky, bounty campaigns are not all true and some are scams. Even if there is no money involved in participating, it is still risky because your hardwork during the campaign will put into vain if it happens to be a scam.