As a non-native speaker, I always defer to the dictionary, which states that neither should be used in a formal context.
What does the American Heritage Dictionary say? There is no such thing as âtheâ dictionary. (Although I agree that careful users of English should avoid âirregardlessâ and âainât.â Usually.)
Like I said - non-native speaker. 
From the American Heritage Dictionary:
Irregardless: Nonstandard
Regardless.
[Probably blend of IRRESPECTIVE (OF) and REGARDLESS.]
Usage Note: Irregardless is a word that many people mistakenly believe to be correct in formal style, when in fact it is used chiefly in nonstandard speech or casual writing
Ainât is similarly nonstandard.
â[Probably blend of IRRESPECTIVE (OF) and REGARDLESS.]â
They are being far too kind. All of the people Iâve witnessed using âirregardlessâ have had no intention of using this awful word as a blend of âirrespectiveâ and âregardlessâ; rather, they use it to mean âregardless.â
That is a major fail, since it is logically an antonym of âregardless.â (the prefix âir-â makes it so)
If someone chooses to reject a college because of one kidâs use of one word one time, they arenât as smart as they think they are.
Yeah â irksome, but probably not insurmountable for most.
Supposably, âirregardlessâ is a real word and so I want to aks why this expecially bothers so may people. For all intensive purposes, I could care less.
There must be some intensive purposes in which it would matter.
@sseamom it wasnât a kid who used the word irregardless. It was an adult former professor who is now an admissions officer at a highly ranked national university. As I said in my post, it was more shocking because she used the word right after saying that there are no excuses for essay errors. However, I actually loved the school a lot and it is currently one of my top choices.
@T26E4 I actually drafted an email saying basically what you suggested, but decided not to send it. A lot of adults donât take kindly to being corrected by high school students (and I would think especially someone in academia). And who knows, she could be the one reading my app this winter.
I worked at a government agency and I wish I had a $1 for every time the head of the agency used the, hmm, word âirregardlesslyâ in talks, letters, chats. Constant. And yet I held my tongue and my job.
Your point is not mute, @JustOneDad 
^ Very nicely done, both of you.
Please, please, please donât do this. A dictionary is a trailing indicator of whatâs going on in languageâit is not (and should never be used as) a way of arbitrating what is part of a language or what is acceptable in a language. And this isnât just me being orneryâIâd be happy to put large money on more than 9 out of 10 lexicographers agreeing with me,* and if the people who do the actual writing of dictionaries have that position, well, then why other people think they should misuse dictionaries that way.
- Source: I know a lot of lexicographers, and frequently attend the same research conferences as they do.
Actually, âdisirregardlessâ is my favorite.
I think if a tour guide encouraged this discussion, I would report it in this thread. So much meta.
On a visit to Case, we got to hear at least 4 times how theyâd defeated Carnegie Melon 8 times in a row in football. It was kind of funny the first time. By the end, weâd blown way past funny and worked our way through denial, grief, anger, and acceptance.
Found the whole visit off putting for reasons I canât quite describe. I guess the topper was the dorm visit. It was on the first floor and the common area was being renovated resulting in ladders, buckets of drywall mix, pipe, and cans of paint scattered around. Once you navigated that to the actual room, you were told âthis isnât a freshman room, this is for a dorm advisor. The freshman rooms are smaller but have some closets.â Really odd.
I canât believe this thread is getting attention again! I had completely forgot I made this 
As a tour guide myself i do have stories from this end. For one, there was this girl from Florida who my boss was stressed about. We had to give her a great tour blah blah because she was able to get in contact with the dean of the school (idk what or why)
Anyway, her brother and father were with her and the dad asked about internship opportunities in her program (communications)
I told her that I have friends who have gotten interviews in their first year, although it was more common to get them during sophomore year when major core classes begin. The girl interrupted me to say, âwell, Iâll be talking to an advisor because I already have people in MTV and vh1 that I know . So they said I could skip some prerequisitesâ to which I said that I canât help her there.
Needless to say her entire tour was about her more so than the school
@50N40W too funny. My D goes to Carnegie Mellon and sports arenât that big of a thing there. Although at football games, CMU students always chant this to Case and other schools: âthatâs alright, thatâs OK, youâll be working for us someday!â
After doing my first tours today, I feel like itâs time to bring back this CC staple. I have nothing special to report on after touring Georgetown and American (American tour was amazing btw) 
but I hope some people have some entertaining stories to tell!