There is no requirement to report. If you want to participate in reporting you must register before the reporting window starts. This costs a small amount of REP and you get it back as long as you show up and report in the next reporting window. If you do not show up the registration fee is forfeit.
At the moment (in beta) the registration fee is hard-coded to 1 REP. Long term the plan is to make it so the registration fee dynamically increases if lots of people are registering and not showing up and decreases if almost everyone who registers is showing up. The goal behind the registration fee is simply to put enough pressure on people to show up so we have an accurate prediction of how many reporters there will be in the upcoming reporting window (this information is used to calculate how many markets each registered reporter should report on).
If you do not want to participate in reporting you simply have to do nothing. Don't buy a registration token and no one will expect you to report and there will be no problems for you.