My question is whether those easy techniques can or cannot trigger safe Kundalini experiences, which I believe are milestones on one's spiritual way. First, kundalini experiences do not seem necessary milestones to me. It is incorrect to conclude that the more dramatic the kundalini experience, the higher one is, or any such thing. Dramatic kundalini experience can happen in beginners and may be as much an indication not only of some awakening of energy, but also of blockages and resistance to the smooth, balanced flow of subtle energies. Through gentle techniques like TM, the blockages are slowly melted and the subtle energies slowly build and flow in a more balanced way.
Consciousness expands in a natural way, without a lot of intensity and drama.
Nevertheless, I am all for accelerating this natural growth through more powerful techniques. In fact, I feel that for most people this is essential to really progress rapidly. Even so, even with the most powerful techniques practices by yogis, one who is very pure and has a strong, highly evolved nervous system, may not experience a lot of so-called kundalini experiences. They will feel, however, intense bliss in every cell and cosmic awareness growing in leaps and bounds, and perhaps siddhis as well. It is very important to have expert instruction in advanced techniques.