IPOD Etiquette

I'm putting this out there, because I'm not sure of the answer. And I hope any Foundation readers may be able to help me out. I know that we haven't posted in a while, so I know that may be asking a lot, but whatever, I feel like our faithful readers will forgive us.

I take public transportation to work...I love it, well most of the time I love it, I hate the redline and it's 10MPH rule on the Longfellow bridge, but whatever, I haven't put gas in my car for like 4 weeks. But what this means is I often have 45 minutes to an hour of time to kill in the morning and again in the afternoon. So I have taken to doing many things to pass the time, sometimes I read a book, sometimes I read any variation of free newspaper or magazine available at the stops I am frequenting. Sometimes I'll read a book, sometimes I'll play Solitaire on the IPOD...and sometimes, I'll watch movies/tv shows on the ipod that I downloaded from the interwebs.

The question I have, is this, the screen on my ipod is pretty small...and in certain lights very difficult to see, but still I worry, because sometimes, not often, but sometimes an image that may not be suitable for all ages comes upon the screen. A random boobie here, a simulated sex act there, you know basic Pay cable type of stuff, but not Skinemax stuff. For example, I watched Beer Fest on the Ipod, and like 10 seconds into the movie, there's a LOT of Boobs. Like dozens of them...I embarrasedly covered up the ipod and waited out the boobs (I went back later, don't you worry I don't turn down the opportunity to see boobs very often). But what's the rule of thumb here?

Do I assume that the screen will be unviewable by anyone else? Do I care? Do I not watch The Wire when children are present on the bus? Do I not watch Weeds, during rush hour on the red line? Please, all opinions are welcome, but I want to know, should only Network aired programming and G Movies be allowed to be seen on busses and trains? I mean obviously, I'm not going to download the Hustler Real College Girls series and watch them on the bus, but is there a line I shouldn't cross?

Thanks in advance for your comments in opinions!