I don't allow employees to carry cell phones around all day, as it hinders their performance. I have no issue with a pistol tucked in a pocket, however, as it is not a hindrance and is not a danger either.
You are not going to accidentally shoot someone with a cell phone. Carrying a firearm in your pocket is a good way to have a negligent discharge. Other employees won't have a problem with colleagues having a cell phone they might with them having a firearm.