... and I've known some who just didn't want to.
Personally, when I worked at a university, I kept a shirt and tie hanging in my cubicle for when I had meetings. As I never wore jeans in, when given 5 min warning, I was prepared.
Unfortunately, one day, I was dealing with server problems with our team lead, and my (new) manager came in and insisted we had to go to a meeting. I said I needed to grab my shirt & tie, but he insisted we were already late.
It seems that the executive director (3 levels above my boss) had decided that we were going to have an 'introduce the different groups within the IT department to each other', and the chairs were set up as rings of concentric circles ... and all of the free chairs were in the middle ... so I'm wearing a t-shirt that says "some people are alive simply because it's illegal to kill them".
Then they started cracking down on the dress code. Of course, the memo from the executive director on this "interpretation of the dress code" included no logos, so the staff shirts were actually not compliant with his interpretation. It also said "shirt with a collar", without qualifying "dress collar" (so therefore, my crew-necked t-shirt was compliant). They also insisted on 'no large text', without defining a specific letter height. (I hung up my White Zombie "More Human than Human" shirt to show that the "some people..." shirt had medium-sized letters.)
I was later fired ... it had to go before the unemployment office as they claimed I quit , but refused to make a formal statement (where I could've then sued for libel ... of course, I likely also had a case for "constructive dismissal" anyway, as my project manager had been told to harrass me 'til I quit)
But ... as my job was all about problem solving, I found a number of ways to comply with the wording of the 'interpretation' of the dress code:
- took the sleaves off of dress shirts. (not a good luck for me, as I'm rather hairy)
- added 'A COLLAR' with an embroidery machine
- borrowed a steel gorget from a friend in the SCA (along with the rest of the platemail)
- bought a number of 'club shirts' (effectively, hawaiian shirts w/ comic book characters on 'em)
- wore the same shirt for almost 5 weeks straight (2 weeks, 1 day gap, then almost 3 weeks without washing it, only febreeze)
- obnoxious ties ... but that was a problem when crawling around the machine room (I was also a sysadmin)
If I had it to do all over again ... I'd have tried to find a priest's collar. Or a dickie. I mean, hell, I worked in a locked room -- it's not like anyone saw me except for when I went to meetings, lunch, or the bathroom.
So instead, I work at NASA ... about the only government agency (unless you're at HQ) that prefers you to *not* wear a tie (I was threatened with bodily harm by a small, 60+ year old woman if I continued wearing one to work). Unfortunately, a while back my employer got bought out by a military contractor, and they started pushing down dress codes on us ... so I've been trying to get a definition of exactly what a "graphical t-shirt" is. My co-workers all just ignore it, but I'm doing my best to point out what a pointless, stupid rule it is w/ ASCII art and stylized text.