[mothered]

Pretty much any site, depending on how you want to SE them

Exactly this.

You're manipulating/exploiting the representative, not the company.

I understand this, but some sites tend to be much easier to refund or Double dip based on their policies. Therefore, which sites are Easy/better to double dip from?

It's hard to provide specifics- If the representative you're dealing with Is naive, gullible and vulnerable to manipulation, the company Is of no significance.

For Instance, Amazon Is easy to double-dip, but I've personally come across a representative who was very adamant and did not budge. Another occasion, I did It with Incredible ease. It's all about who you're dealing with at the time, and how effective your method Is.