You are correct...many diet teas and colon cleansing products use herbal laxatives that cause cramps or griping for many people...senna is often the culprit as it is a very aggressive laxative...cascara sagrada or cape aloes can do this, too.
You will not experience the same type of cramping...if any...when doing the psyllium and Bentonite colon cleanse, or one like Holistic Horizons. Occasionally people will experience some cramping as a result of bloating...particularly in the early stages of the cleanse...or when a large piece of mucoid plaque has dislodged and is making its way through the pipes. But in neither case will it be of the intensity of discomfort that is caused by a strong dose of senna. And many people report that various pains that they have had in different areas of their abdomen...sometimes for years!...have vanished when they did the colon cleanse...including improvements with menstrual discomfort. Also, you will not experience loose stools or diarrhea which often accompany other cleanses that use laxatives.