I did that a few times on Saturday, during Julia's bikewash, checking all the bikes that came through. I felt like we did 100+!!
I am still amazed at how many people have no idea what their pressures are supposed to be, and/or haven't checked them in a year! Lowest was 16 psi on a cruiser, and 22 on a sportbike that should have 42psi. Throw in a Goldwing with 23 in the front tire, and you have a good mix!
It's a good idea to check them occasionally. They last longer, handle better, work better in the rain, brake better, and are safer when properly inflated.
Check them. Use a decent gauge, and don't trust the gauge at the gas station. Check the bike manufacturer's recommended settings, or the tire manufacture's fitment chart for proper pressures.
If you're not sure, ask the person who services your bike.