Here is the answer to your question:
It depends on when you want to submit ERAS.
Say you plan on submitting ERAS on September 1st. The earliest you can take Step 2 and still have the option of not automatically reporting your score (ie "suppressing") is the second week of August, because Step 2 scores come back within 3 weeks. *If you get your Step 2 score back at any date before submitting ERAS, then your score automatically becomes part of your USMLE transcript, which must be sent in its entirety to the programs.
For example, if you take Step 2 on August 8 and you get your score on August 29, it, by default, becomes part of your USMLE transcript, along with your Step 1 score. At this point, you must transmit your whole transcipt when you submit your ERAS application, including your Step 2 score, whether you like it or not.
On the other hand, if you take Step 2 on August 15, you mostly likely won't get your score back until say September 6th. When September 1st rolls around, you submit your application, transmit your ERAS transcipt with only your Step 1 score and hit "NO" on the question that asks if you want to automatically transmit your USMLE transcipt when a new score becomes available, thus "suppressing" your score. If on September 6th you like your score, all you have to do it re-transmit your USMLE transcipt on ERAS. If you don't like your score, then just continue to suppress it and you're good.
This all changes if you don't plan on submitting exactly on September 1st though, but the rules remain the same. If you want the option of supressing, take step 2, click "NO" on ERAS, but don't wait more than 3 weeks before submitting your application, because if you do, your score becomes, by default, part of your application.
If you do suppress your score in this manner, all the residency programs see is that you've only submitted your Step 1 score. They can only conclude that either: A. You've suppressed a bad Step 2 score, or B. You didn't take it either because you thought your Step 1 score was good enough to stand alone or that you didn't want to risk it. So, programs don't necessarily know why there is no Step 2 score listed, but they can venture a pretty good guess.
I hope this helps. If it doesn't, then I'm sorry, and god speed. 😉