'Fast Action Bonus' & 'Scaricity' techniques losing its effectiveness?

I'am sure all of us have reached a fresh sales page like a firesale for example where they include two or three bonus's if you purchase within the next two hours or something similiar. However I sometimes trek back to the salespage a week sometimes two weeks later and see the same exact bonuss with the same line of text "Act now and recieve X-Y-and Z" and to be honest I have almost become numb to this tactic whenever I see it. Very few times have I seen a sales page where they actually kept to their word and removed the bonusus; I am only a single person in this 'game' if you will, (no pun intended) so I'am sure their are others that feel the same.

While keeping the bonuss up indefinitely and claiming otherwise may indeed increase sales because assumably, once a customer makes the purchase properly, they are unlikely to go back to the sales letter and see the 'trickery'. However in the chance that they do go back the the page a week later for whatever concievable reason and they see that the supposedly limited bonuss are still available, does this create or germinate maybe evan the slightest seed of distrust in the mind of the customer?

If this tac is done for each product you launch or firesale you have, wouldent a certain percentage of your subscribers have a slightly tainted view of you? Just curious.

Best Regards
~Ross Vaughn