When one hires a freelancer to do some work on their site. Like fixing some errors you might be getting etc and which one needs to give the programmer access to your sites database, ftp access, admin access etc. How do you ensure your sites data is safe, like user information, your code, the sites files etc.
You cannot unless you send him only specific part which needs to be fixed. Make sure you hire people with many iTraders, and good reputation.
I have that same concern - ultimately, your data, especially if it is on behalf of one of your clients, is YOUR responsibility to protect. If it is very sensitive information, and the person is from DP, I would definitely check itraders (and check the transactions that the itraders were to), reps, past threads and they should have a Web site outside of DP that has customer testimonials that are referenced by the Web site that they served. Only then would be feel even partly comfortable. Otherwise, I would look for someone local to help you ... If it is just for work on one site, why don't you have them send the files to you and you FTP it? Or set up a staging server for them that only gives them access to that one folder and then you move it to the publishing area when ready. Or if it requires script installation or something like that, then yea, you have to weigh out all your options ... good luck!