Some Filipino systems have codes of secrecy. Then there are those that advertise on the web, writing:
"An invitation to join the training group is a unique and exciting opportunity. However, membership in the group is not for everyone. Join the group, and for life - You are bound by the Warrior's code: Honor, Loyalty, and Silence. We firmly enforce the social responsibility that accompanies the awesome destructive power of this skill and art. For this reason, Group members must swear an oath to never reveal our practices outside the group. This preserves the combative integrity of the group."
What got me about this is that they have pictures of what they are doing, and they sell videos for $20 for each belt rank! How secret can they be if they're peddling their art online like that?!! Just having belt rank is a tilt towards commercialization of the art. Posting your school and pictures online is the antithesis of secrecy. Selling tapes for rank ... not secret at all! At that point, if they have secrets, it's that they are holding back on the good stuff and not really teaching with full integrity. IMHO, anyway.
Right up front they state that they are not a new method or style of FMA, they've simply categorized all the drills they have found in all the systems they've researched and systemetized them. If they've taken knowledge given freely, how is it they put it back into the dark? Maybe they're recruiting mercenaries from the ranks. I don't know or care to find out. That's their business.
Some systems don't require loyalty oaths until certain levels are reached. Others have incremental steps, such as "don't show or tell" for beginners, a blood oath for the hardcore elite.
Me, I believe in freedom in martial arts, and every day I thank my teachers for allowing me to have the freedom to explore and grow on my own. Most people don't undertake the rigors of training to become pliant and controllable drones, they want to become strong people in their own right. Martial arts were about resisting oppression, taking responsibility for one's own destiny, insofar as one might. There are times and places where secrecy has been necessary, such as guerrilla warfare where the lives of you and your associates are in danger. In a free and open society, however, secrecy is a way to brand loyalty, a brainwashing tool that demands obedience to a hierarchy. It is a large part of what defines cults.
In the end, people may choose to leave anyway, engendering hard feelings between those leaving and those left, and what can be done to prevent someone from going? They could get a court to issue a gag order against the wayward member, or resort to intimidation and violence. At that point they've pretty much destroyed the integrity of the art that drew people to it in the first place.
Think and choose wisely, because much that is purportedly hidden in such groups is freely distributed elsewhere, and if it is truly secret, it surely isn't advertised!
Life is pretty much defined by two primitive impulses: attraction and fear. Psychologists from Wilhelm Reich to B.F. Skinner studied these. Training animals (and people) nowadays owes much to understanding this. Obtaining willing behavior is generally faster and more reliable than coercion. Try punishing an 8,000 lb. orca at Marine World and your trainer has just become bait, but with rewards and encouragement, that animal can learn all its tricks and routines in 9 months, plus many behaviors required for care and maintenance. Offer a kid candy for trying to answer a math problem. Give more candy if the answer is correct. How would this affect behavior compared to yelling and belittling? The old saying was "you catch more flies with honey than with vinegar."
Blood oaths and secrecy are about power and control, the dark side of the art. What is it that is so greatly feared that such strictures are imposed? Is it fear of the outside world, or a lack of trust of those brought into the clique? Looks like the latter to me.