the trading one is normal , the other traders aren't responsible for others' mistakes and they may be using bots as well
overall I can't see how this can happen , even if you put small orders the exchange should be matching you with the highest buy orders
unless you are doing it with a small coin and that can be explained as a try to dump the market and get rid of that coin
There are already scenarios where this could happen.
Many of the bots are self-developed and adapted to best suit the trading behavior of the bot-owner.
A simple bug that could lead to the loss of a lot of money would be, for example, a comma error. In German-speaking countries, for example, 10k is written like this:
10.000,00
In English-speaking countries in particular, however, the exact opposite is true:
10,000.00
If you as a developer make a mistake and you place a sell order for 1 BTC for 10 dollars instead of 10k dollars, this is a rather painful loss. In the early days of the Exchanges you have seen something like this in the order books from time to time, e.g. on bitcoin.de, where coins were set at 10% of the market price - and the orders were of course filled immediately
But I'm with you on this: It's definitely no "offence" of the buyer if someone places such a sell order.