Personal opinion? Don't bother. It is not an infrequent event for people to try to access folders (directories) that they are not allowed to - often innocently. As long as it is blocked from them, then as the saying goes, "no harm, no foul".
Indeed, there are times when auditing is appropriate, especially with systems that have enhanced security requirements. This is why there are the SELinux extensions (Security Enhanced Linux) and implements access control lists, and such. You might want to look into that.