Jiu jitsu is most definitely its own culture... and as with any culture, it has its own set of taboos. Taboos are those things or actions that are looked down upon by the majority of the community's members, either because it's seen as repulsive, as a violation of tradition, destructive to the culture, or just simply against standard practices.
Keep in mind the operative word here is "majority." Just because some people consider it taboo, doesn't mean you have to blindly follow it. Definitely decide for yourself what you believe and go with that. Without further ado, here are our top five taboos in jiu jitsu:
Washing Your Belt
One of the oldest superstitions in Brazilian jiu jitsu concerns washing your belt. A lot of old - and new - school practitioners refuse to wash their belts, considering it a kind of "washing away of knowledge" obtained on the mat. Athletes in general are a superstitious lot, with all kinds of habits and practices that make absolutely no sense to anyone else but them. This is natural and completely normal (and quite humorous, as well). Whether you subscribe to this superstition or not, it's important to know why some do not... The primary reason concerns hygiene; your belt, like any article of clothing, absorbs sweat and houses bacteria. Therefore, a lot of BJJ practitioners regularly was their belts, if not daily.
Belt Promotion Gauntlets
A lot of academies have this peculiar tradition during their belt promotions: the gauntlet. No, it's not a medieval metal glove. The word itself actually comes from the Swedish word "gatlopp," meaning to "run the gauntlet," which referred to "a form of corporal punishment in which the party judged guilty is forced to run between two rows of soldiers who strike out and attack them." While a typical BJJ gauntlet isn't meant to be a form of punishment, it still involves two rows of your fellow practitioners inflicting some well-meaning and friendly (usually, anyway) abuse upon the newly promoted student with their own belts. While this practice continues in a lot of academies as a sort of "rite of passage," many academies have begun to abandon it, largely due to outside criticism or their own beliefs that it can be brutal, excessive or unnecessary.
The word "creonte" originated in the Brazilian jiu jitsu community and is used to refer to a student who switches academy affiliation, particularly if he/she had a very long-standing relationship with the former academy. This term is usually associated with more traditional BJJ academies, while more modern academies - many of which were built on drawing upper belts from other academies and locales - typically shrug it off. There is quite some heated debate concerning the word, however. Those who subscribe to it argue that a student, who has been given years of training and support from the original academy, is unforgivably disloyal when he/she leaves to join another academy. Those who oppose it claim the original professor and/or academy is afraid of being seen as inferior and that a student has every right to leave if he/she feels another academy will fit his/her needs, personality or game better.
Cross Training with Other Academies
Related to the idea of a creonte is that of a student from one academy training periodically - or regularly - at another academy. This is also a hotly contested topic. For some, training at other schools not only demonstrates a lack of respect for the original professor and academy, but can also create problems as it relates to competition and representing a team. If a student is training at two (or more) different academies, who does he/she represent? If he/she giving away too much of the academy's game and strategy to a competitor? On the other hand, proponents of cross-training argue that it only helps a competitor grow his/her jiu jitsu, and that of the academy as well, as he/she is bringing back fresh ideas. Of course, there are those academies that have great relationships with each other, and thus cross-training is completely accepted; as well as those academies that are bitter rivals, in which cross-training is strictly prohibited.
Dating Within the Gym
And now to the taboo that afflicts any kind of gym environment: dating within the gym/school/academy. Whether it is open or on the down-low, if there is a substantial group of both men and women on the mat, odds are there is some dating going on. Which is a perfectly normal phenomenon with any group of people in which the members share the same passion and spend lots of free time together. However, this can cause issues. In the case of a breakup, who gets the gym? If both individuals choose to stay, it can cause some tension on the mat, even for the other practitioners. However, there are definitely some jiu jitsu couples who have demonstrated that a relationship with someone from the same academy is perfectly fine. These couples typically do a good job of keeping their occasional arguments away from the mat.
As I mentioned before, whatever side you take and however you feel on these subjects, that's on you. You're entitled to your own opinions... just as long as you keep training and allow others to have theirs.
Train on... respectfully. Oss.