I wonder, given the very significant effects meditation can have, if it is appropriate and safe for meditation techniques to be taught and shown in an uncontrolled environment such as that provided by Prem Rawat where absolute no follow up is given. 

When K is revealed, there is follow-up and there always has been, as far as I know.  Maybe in the old days there was an "uncontrolled" environment but nowadays, K is given in a very controlled environment.  Great care is given to the noise level, comfort level, temperature, etc, before a person receives the 4 techniques.  And there is very definately a follow-up.  Heck, one of the promises made to receive K is to "stay in touch".  If questions remain, they are addressed.