I've only used the HTL group 4 times, but for me, once I got over the first time jitters, they became "safe" for me because you know the process and know its legit. But I say that staying with the same location/city. The one I use has been at the same hotel for the 4 times I went so I felt comfortable going to it. I would probably feel anxious if I were to try a HTL group in another city. For the most part, as mentioned in the other post, they are older flowers.
