Who was it that said something to you? Was it someone that also wears and uses diapers or someone close to you that knows you are wearing diapers?
I have been wearing 24/7 for at least 15yrs now and so far no one has ever said anything about seeing or knowing I am wearing a diaper. There are at least 2 large events that I work at each year and I am being seen by 250-500 people while I am on stage and or walking around the event and no one has noticed. In fact, one of those events was this week and I was in dress pants, shirt, tie, and jacket up on stage and walking around, no one was the wiser. I was actually wear a Purple Rearz diaper.
As others have pointed out, the type of clothes you wear and how you wear them will help hide them. I wear my clothes a size or thee larger to help hide them.