Not exaxtly, for me buy before it be listed and when listed sell it. That thing is profitable base on my experience.
Participating in ICO nowadays is not that good as you say. We all know price drops as soon as it hits the exchanges because of bounty hunters. In my case, I prefer buying after it hits the exchanges bacause most of these tokens drops for more than 50% its ICO price.
Not the entire ico going downwards once after getting listed to the exchanges. At times the price used to increase, so we need to make use of the opportunity analyzing the market. I've benefited through the newly listed coin, same time investing on these assets were highly risky.