I agree that most conflicts tend to go unnoticed when the symptoms are momentary freezes or intermittent lag,it tends to take a BSOD for people to take notice.
Actually delays and lacks can and do indeed are noticed. Negative interactions that lead to gaps in security will not be noticed.... for obvious reasons...
It must have an adverse effect on malware detection and prevention if there are resource conflicts,so excessive security apps can have the opposite effect to what was intended.The problem is that you often have to delve deep to see exactly what is covered by each application in order to prevent overlapping.
There seems to be a misconception here. Most people seem to talk as if avoiding "overlapping"
is what is required to avoid problems like the one between TF and comodo leading to reduced possibility of detectinbg keylogging...
Besides I notice that most people conceptions of what constitutes "overlapping" or not is based on reading superficial marketing speak crafted by product PR trying to differentiate themselves from the competition...
One is "intelligent", one is "community based", one uses "whitelists" , one is "Sandbox"....
Sadly while such concepts are not utterly 100% falsehoods it says nothing at all about whether such products will or will not overlap...and cause conflicts...
Take antivirus and firewalls (the classic ones), surely you can't get less "overlapping" then that. And yet conflicts do and can occur (and i don't mean just BSOD types).
In fact, the "pseudo-expert" wannable types who frequent such boards are more prone to this, because unlike ordinary people they are much more capable of distinguishing between security product functions, hence they are much better at convincing themselves that products don't overlap and/or feel the need to combine products "cos each has functions the other doesn't have"....
While the average user might possibly be happy to have a HIPS, a "expert (or what passes as one here)"
can distinguish between a behavior blocker, a sandbox, a hips (or whatever conceptual scheme he favours).
And i can go further and distinguish between types of sandboxes etc...
The next logcal step would be then to convince oneself that one needs all of them because they are actually quite different and hence aren't overlapping...