IFMA is not an open tournament...each country sends a team represented by qualifying athletes who won in their respective divisions at local/regional/national competitions. not sure what the scene was back then in poland but it's not like joanna just walked in and asked to compete.
in terms of the gear they have to wear, it's based on competition categories; there are a total of 3 categories - 2 for male, 1 for female.
male: competitve class and elite class
female: elite class
the elite class for females is a catch-all so you have pros and amateurs fighting against each other. you will see pros like janet todd (boxing works) from the US fight with full protection even though she fights pro muay thai. so joanna having to wear protective equipment is a part of competition rules as there is only ONE division.
at least she didn't have to wear anything else like in competitive class for male, they MAKE YOU WEAR A CHEST PROTECTOR.
source:
http://www.ifmamuaythai.org/technical-reference/muaythai-rules/weigh-in-and-classification/
according to her wiki, her muay thai championships are IFMA and WMC...so those are legit.
her kickboxing ones, i am not super familiar with:
- J-Girls Kickboxing Federation
- World Budokai Federation
- World Kickboxing Federation
- WKF European Champion (2010)
- World Kickboxing Network
- WKN World Champion (2010)
in any case, her wiki page looks to only have fights from 2012 onward and misses a lot of her actual pro muay thai/kickboxing fights.
a quick search on youtube:
this one was a pro fight in japan from 2009
another one from 2010
2011
edit:
let's not confuse muaythai and kickboxing.