Regulasi aren't a golden bullet against scammers. As all those things become more obvious to the general public, scammers evolve to mimic decent projects with almost impeccable efficiency. Still, the most reasonable rule of investment isn't about ICOs or IPOs, it's just about your common sense. I mean no matter what, never spend more money than you can afford to lose.
I agree with you when we make investment in cryptocurrencies the projects must have regulation because it will protect the investors of scamer, however the cryptocurrencies projects (ICO, IEOs projects) mostly of them are start up and they does not have real of businesses and products. Also never spend more money than we can afford to lose is part of risk management investment in cryptocurrencies space, that's why we need planning on investment than just think about the profit from investment.