It is not safe, totally not. If you just follow ICO blindly, not reading anything like whitepaper, then you are in close proximity with scam.
On anther note, to evade such unfortunate event, read their whitepaper. But do be careful still, many scam projects have laid out quite the impressive and convincing whitepaper. Having said that, not all scam are prepared with crappy proposals.
On another note, it is best to follow same dev team that you have worked and trusted before. In this manner you can really say that it is safe to participate.