There are many exchanges that are faking volume. Some reports show that there is up to 90% wrong volume reports. With market developing i am sure there will be more strict rules and penalties.
I think this is the next step in crypto for further development.
There should be some index be issued based on volume to track real volume of top 10 or top 20 exchanges who should be then monitored by some external company.
I hope also CoinMaketCap will take this issue into consideration soon enough to get some real data on smaller exchanges as well.
It is a very bad practice to upload wrong or fake volumes just to attract investors. These are some of the things that get people discouraged when they eventually find out that all their labour has been for nothing. It is sincerely very bad and I think I penalties should be attached on case of anyone found defaulting in this regard. Truth should be the watchword any day anytime. That will afford cryptocurrency a beauty beyond our description