OK, it seems in most cases my approach would work.
But before going to work I would have to identify if the site might cause
problems.
Use of SQL database is obviously one thing I have to find out about. Is there
a way to confirm the use of database WITHOUT squeezing it out of customers? I
mean just by looking at the site?And the same question about scripts. I have
programmed 15 years ago at school ;) and I am capable of reading and
understanding script texts to some extent. What are the signs of danger to
look for? 	
As you see I would like to avoid dependence on customer-provided info as much
as possible. In many cases they do not have a clue what they are talking
about, in other cases they become suspicious about my motives if I ask for
full source etc.etc. But their money is still good :))

Wahur