If your diaper is really thick and full of pee then it could be possible that someone could see your diaper bulge through your pants or shorts.
Especially if you wear sweat pants the diaper bulge in the back will show through more than in blue jeans.
I've worn diapers to school and wet them and I could see a slight bulge in blue jeans but not sure if anyone else noticed.
If they did notice they didn't say anything and they probably weren't thinking they were diapers.
I can clearly see a toddlers diaper bulge in the back of their sweat pants when they are wearing a diaper and sweat pants and when it gets full.