Some MAA events have a dress code and some do not. It depends on whether the event is sanctioned by USA Archery or the NFAA. The dress code may also depend on what division the participant is shooting in.
Any event sponsored by USA Archery including, for example, the JOAD State Indoor, the 25-meter Championship, and the Voyageur Cup follow the USA Archery dress code.
You can see the complete USA Archery dress code on their web site. In a nutshell, the rules are no denim with holes and shoes must cover the entire foot. Leggings must not be transparent or translucent above the knee. Please read the entire document for all the details.
Competitors in the NFAA professional classes at NFAA sanctioned events must abide by the NFAA dress code. There is no dress code for other participants (within the obvious bounds of decency, of course).
The NFAA professional dress code says: “Professional archers shall dress in a clean, professional manner. Bottoms should look fitted, clean, undamaged, and be of appropriate length. The waist of the attire shall not fall below the waistline. No ripped or frayed jeans. T-shirts, swimming suits, cut-offs and obscene or vulgar slogans or pictures on clothing are prohibited.”
The complete NFAA dress code can be found in the NFAA official constitution & by-laws.