If it were me, I wouldn't worry about getting the photo memory card back into the camera. When my wife took my personal prescription info (a violation of the federal HPAA laws), and I found them in her drawer, hidden away, I just KEPT them. "a", they belonged to me anyway, and "b", I found it kind of amusing that there was NO WAY SHE COULD ASK ME for it, cuz to do so, SHE'D HAVE TO ADMIT SHE TOOK IT!!!
But if you think that getting it safely back could allow you more time to collect more info, then I guess that would be good. I also always like to see someone be in a position of being able to say to their cheating spouse "I know all about you and _______," and NOT reveal the source of their intel, as the cheater then doesn't know what you know, doesn't know what you DON'T know, and therefore has to assume that you know EVERYTHING!
