I read on another topic " I remember when I used to carry microphones years ago in the JW cult- only about 30 % had their WT's pre-studied, the rest just wing it I truly believe" and it reminded me that people will assume you are not familiar with the material if you have not underlined, and that there will always be those who observe the lack of ink and consider you must be unprepared (and so 'weaker' than them).
Many times I used to fake prestudy just for that reason. Its easy to do, underline a random sentence or 2 in each paragraph or the sited scripture. You can wizz through an entire article in 3 minutes....did anyone else do that?