It would seem that "Wash Trading" is a much bigger problem than originally thought. Wash Trading is the buying and selling of coins by bots on the exchange to artificially create volume and the perception of liquidity. A new study shows that only 3 of the Top 25 exchanges trading Bitcoin according to CoinMarketCap are actually presenting true figures. https://cointelegraph.com/news/report-claims-over-80-percent-of-top-25-btc-trading-pair-volumes-on-cmc-are-wash-traded
I also heard about those bots that can really control the volume and liquidity of an altcoin. In my opinion, we should choose a good trading platform or exchange in order to be safe about this incidents.