yeah - ive run into this, as well.  it's a disappointment but if you kinda go with the mentality of give, not get it stings a little less.  geocaching is one of the few times where it's all about me.  last person didn't leave anything? fuck them, im so much better than they are.  here's a trinket for the next guy. /proud of myself silly but it works for me.  :)