Technology and Rudeness or not?

Hmm...Using my mobile more and more for taking notes at meetings/courses etc. but hard to not look like it's rude as can appear like I am constantly texting. More practical and efficient to do as can email notes to myself after and save them without having to type them out afterwards from handwritten notes.  I usually run it by or ask permission from the person giving the course or chairing the meeting etc. but not everyone in the room would know why I was typing on my phone so much and may be offended!  Dilemma but makes sense to do it with never ending to-do lists!