Where have you "always read" this? Please provide a citation and/or a link. And what would make you think someone would lose the ability to report something to anyone solely because of the passage of any amount of time? I hereby report to you that, when I was 10 years old, I committed several misdemeanors when I and my friends, on multiple occasions, stole baseball and football cards from local stores. There: I just reported to everyone who reads this thread misdemeanors that occurred over 40 years ago.
I assume you're confusing the reporting of a crime with a statute of limitations. One can report anything to anyone at any time. A statute of limitations is a law that limits how long the state has to file criminal charges against someone after a crime has allegedly been committed. In California, the statute of limitations for most misdemeanors is one year, and statutes of limitations for felonies range from three years to no statute of limitations at all.
Aside from the fact that is quite unlikely that anyone would call 911 to report a minor crime that has already been completed, it is utterly impossible to predict intelligently how likely it is that a hypothetical individual will or won't do something.
Who are "they," and what does "wait that long" mean? Wait how long? And I have no idea what the part of this question after "try and trick" means. However, again, intelligently predicting the likelihood of a hypothetical person doing or refraining from doing something is impossible.

