I think this is very true. To be safe, you should assume that only the first bids and asks are genuine (maybe also second as well). All the others are probably fake orders, and even if they are not, you had better think that way. But you can learn a lot just by looking at the order book and its evolution in time. Just spend a couple of hours looking at it, identifying bid walls, number of orders, bidding pressure, and supply and demand runs. It may give you a good indication of the market.