I've never met a teacher in any physical activity (ranging from zumba to soccer to martial arts) who thinks you can skip streching. YET everyone has vastly different ideas about streching which is understandable. Afterall, soccer uses different muscles than Aikido so why strech the same.
To my understanding, ballistic streching is not very efficent and many suggest it is down right harmful. Yet that is what our main sensei does here. (Personally, I have to admit I deviate and try to hold the streches to make them static. He's never said a word to me, although I try to be as nondisruptive as I can.) We also have a yudasha who is a certified chiroprator and has flat out said ballastic streching is bad for you.
All of our black belts have their own verisions of warm ups that draw from their life experience. One who boxed, for example, has us do 'on our feet' warm ups before sitting down and breathing. The chiroprator has us do static streches.
This makes me curious about other dojo's warm up. What do you guys do? Also, if you can't do what the sensei is doing (for medical/ safety reasons) do you deviate or try to stick it out?