As one who both receives and sends this stuff I feel sure its non appearance is not malicious. Every club I know of seems happy to advertise other events. This year more than ever I am aware of the increasing amount of bumff randomly distributed around venues, i'm not surprised that some gets inadvertantly left at home. Add to that the stuff sent direct to venues which sits under the bar for three months before the club organiser receives it and the ones that are sent to organisers who left the club five years ago / moved house / died and the odds on your bumff getting seen are reduced considerably.
If you're sending stuff out regularly it's worth an evening or two on the phone every 6 months just to make sure you address book is up to date. After that cross your fingers and hope for the best.
All the best