Why do you think many teachers/except GEM/actually prohibit their students to cross train with other teachers? It is human nature and fear of looking bad.
Ted Dinwiddie »
One aspect of cross-training is the opinion of the instructors involved. Some instructors will not like it and others will be in full support.
There are egos involved and you may alienate yourself from one school because of your affiliation with another.
Then there is the ability to bring another aspect to your training and that of the others in your school.
Some instructors love outside perspective and can work from that to further your understanding of their own concepts.
This leads to the common recommendation that one should reach a dan-level rank in one's core style before branching out.
The point being that you have not reached a level of knowledge and competence in the basics of a particular style sufficient to fairly compare or supplement with another. I don't know.
It would have confused me to cross-train at my early kyu level, but that doesn't make it bad for you.
Maybe you don't have a core style (yet or never) and you are still checking stuff out. Cool. It can be difficult to attain rank in two styles at once; very time consuming, for one. Maybe rank means little to you and that is fine, too. But, without being invested in the curriculum of a particular school or system you may miss out or be excluded from some training.
Special "brown belt practices" and such. It can also depend on the similarity of the styles. This does not apparently apply to you, but I remember a young woman in my school (Okinawan Kempo) who was simultaneously practicing another style of Okinawa-derived karate.
She actually demonstrated some of their core techniques when asked to perform some of ours during a test. The validity of the techniques was not questioned, but she was testing in a particular style and curriculum for a low-mid kyu rank. She did not pass.
I started in one style of karate (Ohshima Shotokan) and met with little success in that curriculum. I drifted away from MA in general for a while, but felt the need to be part of a practice somewhere.
I then found my current instructor. Ten, or so, years later I reached shodan. I have just begun cross-training for the first time, in judo.
It is important to realize that the karate school I belong to and came up in is a very inclusive place. We all attend as many seminars as possible and invite other styles to come and train with us.
So I was not ignorant of other points of view. But to be learning basics again and from a completely different direction is a blast. As a matter of fact, the judo basics are dovetailing quite nicely with what I have already been learning.
So, be wary of dividing your available focus to the point of diminishing overall gain. But, remember that there is always another way to accomplish everything.
ted