This thread is interesting to me, as I recently made a “do-it-myself” retreat in a little town near here. Basically, I brought some recordings of a retreat Bishop Sheen gave in the late 70s – which I downloaded onto my MP3 player from the Internet for $15 (I’d be glad to share info on this if anyone is interested) – and listened to them in front of the Blessed Sacrament at a beautiful old church that is open all day. As I felt the urge, I would pause it and pray or jot a note down in my journal. It worked pretty well for me, as I have been unable with family and financial concerns to make a “real” retreat this year and Bishop Sheen was one of the best retreat masters ever.
However, I had the same concern as the OP about what others visiting Our Lord might think I was doing with my MP3 player in church, that is, whether I would be causing distraction or scandal. This is why I stayed in the un-airconditioned church rather than joining others in using the little perpetual adoration chapel nearby, which did have AC. The way I resolved my problem was to listen as unobtrusively as I could (with only one ear bud in my ear) and try to keep a reverent/attentive posture in the pew. Aside from that, I decided that what others might think of what I was doing was not my concern, as I was not flaunting my MP3 player in front of them. Frankly, if someone is examining me or my behavior that closely in church, I would think that s/he is the one with a problem, not me!
So, I think that as long as one is discreet and indicates by posture (attentiveness, holding a rosary, etc.) that s/he is praying, others’ reactions should not be of much concern.
Hope this helps.
Kristen