Charlotte,
I think you may be a little paranoid , you are far more aware of them than can be seen, obviously if you wear one too tight you can see where the main bra strap is restricting your body and leaves the tell tale ridge of skin. If you wear one every day, you will be less conscious of it and other people will just get use to it.
Please don't do what I did and forget to take out the booster pads, I realised walking down my high street the attention I was getting and another occasion I was stopped by a group of policemen while walking the dog after an incident at a local young offenders centre. One of them had most of his conversation with my chest, I nearly wrote to Wonderbra to tell them how well they work !