I think yes the 2nd account can be affected so make sure that you are dealing with trusted sites.
While searching I found a site with reviews and complains about the site it looks like there are many bad reviews about this site. So, I suggest that you stay away from them.
Take a look at this link
https://www.consumeraffairs.com/credit_cards/vanilla-visa-gift-card.htmlSo, this site is totally scammed.