... thus, I contacted the IDPA Area Coordinator a couple of months or so ago and asked him about polo shirts or race shirts, etc at matches as long as the handgun, etc are concealed.
The response was that we could allow the polo, etc type shirts at Tier 1 matches, but they wouldn't fly for the Tier 2 and above matches. 
And this is coming from an individual who has been involved in local, state, regional, and national matches over a lengthy period of time.
Thus, I will take sole responsibility as the Match Director for IDPA Nebraska for making the executive decision to have our matches in compliance with Tier 2 and above so that those shooters who participate are "practicing" in the IDPA match environment with the garments that would be expected of them at those upper level matches.
A shoot-me-vest or a construction-worker-don't-run-me-over vest is NOT required. 
One can use a button down shirt (from top to bottom) that the shooter needs to move out of the way as if it were a vest in order to acquire his/her handgun and magazines as long as the arm raised compliance is met. At matches, I don't always wear a vest...I have worn my long black button down shirts (as I do when I am walking around in my real life) and I have even worn a long clinic gown to simulate being in a health clinic environment (which so happens to be what I do part-time and where I am allowed by the owner to carry concealed).
I have been to only one Tier 3 match, and no one of the 165+ shooters had anything but a vest. I will be at a Tier 2 match next month with bullit, and we will certainly make observations and ask questions.
I can also certainly go up the chain to IDPA HQ and get a final clarification as HQ is very intrigued with our nomad type of approach of starting and spreading the sport in Nebraska by not being wedded to a single range (IDPA Nebraska was granted its own Club Member ID # which is atypical since usually it is the range that has the club #), but I stayed with the Area Coordinator's remarks because of his close and long-term relationship with IDPA HQ.
I appreciate that you asked "higher up" about this---but boy do I not understand their comments.
I'm not surprised that at higher level matches everyone wore vests, because they are simply faster. However, last I knew, IDPA was rather strictly against people wearing "competition-only" gear, and if they are now saying that people can't wear normal shirts and effectively have to wear an IDPA competition uniform to shoot, that rather goes against what they purport to believe in...
The idea that a normal polo shirt, used everyday for standard concealment, is now not legal in IDPA competition for concealment, makes no sense to me. Did the AC actually cite any rule regarding "allowed clothing" or anything?
Looking at the rules, section 8.9 covers concealment garments---and nowhere in there is there any mention at all about "no closed-front shirts" or anything similar. The only requirements are in regard to what it must cover and when, plus additional commentary about how you can't alter your garment to make things easier.
So I wonder where it came from? The rules clarification updates that periodically come out have made no mention of anything like it.
I am overall amused by the fact that to shoot IDPA, I have to buy a different holster and a different concealment garment to use strictly for this competition, because the AIWB holster and polo shirt I use for concealment
on a daily basis isn't legal for IDPA competition, and instead I have to
game it by wearing an OWB hip holster and vest.
Note: This commentary isn't a diatribe against Aldo or anyone else at our local IDPA matches. Like I said, I appreciate that Aldo checked with higher up, and is attempting to run matches so that people will be ready for how level 2 and 3 matches are run.
I just wonder what the AC's justification is for saying that polo shirts for concealment will
not be allowed, as opposed simply saying that they
aren't optimal for higher-level competition.
