Many people use burners and many use Google voice, etc.  I prefer a burner phone.  There's no link between that phone and my civvie life phone.  I believe LE can figure out how to trace an app back to the actual phone it is installed on.  I freely admit I don't have any idea how difficult that is.

I'm an infrequent hobbyist, so Google Voice works for me. I don't install it on my phone to ensure separation from "real" life and the mobile web app is pretty bad. But it does the trick for me every couple months. I just use a private browser (Frost + is my favorite) to ensure it never invades my phone. If I participated more frequently, I'd definitely use a burner phone.

If you're only partaking occasionally, I would stick to a Google Voice or Hush application. Then I would install them into a private folder of sorts (I hope this makes sense).  

 
However, some providers do require that you provide your real world phone number for screening purposes and your "burner" number for discretion when communicating day of.  

 
Best of luck!

 
LJ, xx