Absolutely not.
I had this happen to me. I called in sick, went to the doctor and got a prescription. While waiting on the pharmacy to fill the prescription, I walked out into the Mall to wait for the prescription to be ready.
Some girls from work saw me and reported it to the boss. Of course, I had my prescription receipt with the date and time and a note from the doctor. My boss called these girls in at my request and told them what a mistake they’d made by “assuming” and what that made them by doing so. You know the old saying….
I once saw a guy in Wal-Mart when he was supposed to be at work. I didn’t say a word. He saw me when I saw him. He goes back and rants and raves to his supervisor. He got a lecture from the Big Boss when he went in and said he knew I didn’t like him and that he was sure I told him what had happened. I hadn’t…. Even not liking the guy, I assumed his lead had asked him to go or he was taking an approved break. Not my problem and I didn’t stick my nose into it. So, he essentially told on himself.
It’s just better not to start these games with co-workers. Besides, sometimes we need a mental day… Unless it affects you or is a habit, why spoil life for someone else. This could have been a day where something terrible happened, a break up or even something else bad. Leave it be and wish them well. You haven’t walked in their shoes… don’t assume.