Yes. In my previous organization round neck tees weren't allowed until one day I was out for the whole day completing some formalities at my hiring co. near my office zone and had no time to again go home and get changed my selves as it was almost my shift time. I cancelled my cab and headed straight to my office. I was wearing a levis green round neck tee with no foolish slogans. And I had just joined the co. some days prior.
As soon as I entered my floor and then in my cubicle, my manager and seniors didn't notice anything unusual but one of my team mates pointed out that he (I) was wearing round neck tee and only then the managers made me understood that only collar tees are allowed. I apologized and explained them the whole scenario and how I would have missed the office or could have been late if I had preferred gong home and come back again.
There was no fine or warning.
But following next week, my seniors themselves came to office in round neck tees and since then the traditions continued. I dint questioned them but its was like now if they can why cant us???
I think I made a revolutionary change in my company coz after that everybody was seen enjoying round neck tees. I dont take the credit though but thats what I observed. And thereafter collar tees were seen just 1 in 50.
In fact after some months our onsite team from Nevada and Mexico visited here and they too didnt object or insisted on any such particular dress code. So guess all was fine.
.....And for others who are fighting for formals vs casuals, its totally their personal taste.
What I believe is dress decently. Decent means dont wear tees with any slogans no matter if it reflects patriotic sentiments or love towards ones community/country/flags. So avoid tee with i love u, fship and love quotes/messages/or bullshit fb, whatsapp status and tag lines and also graphics of your fav singer/stars/cars/bike etc. and many more to think about.
Wear one which is plain enough no matter what the color. Brand name is welcomed such as levis/nike/adidas/armani etc.
Also your shoes shouldn't be from
Govindas wardrobe...pink with lime lines sky blue textures etc. or some hanky panky shit combination.
In short, dress such that your overall outfits matches everything
and doesn't feel somethings weird or embarrassing.
Mind you, your promotions and relations also matter how well you dress as well.
So for meetings do wear formals with or without tie no matter even if your manager comes in jeans. So dress as per the occasions and situations.
Dont take any undue advantage if casual wear is allowed in your co. Its for your comfort and convenience a co. doesn't apply or force a specific dress code. But that doesnt mean you treat it like a kids birthday party or picnic. Some ethics should be strictly followed with some common sense.