Not necessarily and you way of thinking is wrong. People think they can get rich by riding the pump and dump wave but in reality it is an illusion. People who talk about such groups are actually brain washed into thinking so. The only people making money from such groups is the owner of that group. They create fake buzz and pump coins making their group members buy them while they sell their coins and get a good profit in return. Moreover they make money from paid memberships. Its all in all a scam and a pretty dirty one full of smoke and mirrors.

However if you are day trading on your own then you might get lucky to join the wave in which case you can profit by selling at a set point and then buying back again at low price.