ATF Test Generator - in which instance do you generate the tests?

Hi, we would like to use the ATF Test Generator to generate automated tests. 

Our concern is that if we generate the tests in the testing instance, the quality of tests will be poor and the tests will be inaccurate because the testing instance does not reflect the actual activity happening in the production instance.

A possible solution is to generate tests in a different instance and transfer the tests to the instance where we want to execute them.

Question 1: Generating tests in production seems risky. I suppose, that the tests are actually executed during the test generation. So it could trigger unintentionally some processes and create temporarily dummy tickets. Am I right ?

Question 2: So cloning production instance to a pre-production instance seems to be the best solution. But I am wondering if it is actually useful if the clone doesn't contain transactional data.