No matter how hard you work covering up "security holes" in your protection system, a hacker will always find one that's left open.
thats true, i would try and close them once there found.
So do lots of systems. What's to stop them just disabling your check? Presumably you have some kind of anti-debugger code?
yes theres detection support of all known mainstream cracking tools. there's other pitfalls for the cracker behind the scence filesize validation ect...
@xlsior, correct and this is the best way to do it, dont let the cracker know they was detected until sometime later.