Benchmark prizes for #facebook fans

Why do businesses have contests where they reward the 1000th fan (or any benchmark?) Don’t they realize that doing a silly contest like that won’t make them get to 1000 any faster? I mean really why would I want to be fan #997 when I can get a really cool (or potentially really cheesy) prize for being # 1000.  I’ll just wait for 2 suckers to come along and click the like button before me.