The reality is that the server doesn't have the population it once was where you could go in and spectate and probably find someone cheating, the majority of the population that play now (especially on conquest) are people who have played for years and have thousands of hours on the server - who are fairly unlikely to cheat. Staff also don't want to be spending hours spectating players who 95% of the time aren't cheating because its mind numbing as fuck and you also have to be watching consistently looking for hard to spot signs that someone is cheating.
In an ideal world you have hundreds of people wanting to be staff who are willing to dedicate hours into watching suspected cheaters and knowing exactly what to look for, but you can see how unlikely it is that staff would want to do that, and are even capable of doing that.