I know this is a month old, but the topic was only brought to my attention today.
to gtasnp.com (meant to do it a long time ago and forgot anyway). The short of it is:
Yes, I do store the IP address of every uploaded with the save file information. The reason for this is to protect the site from anyone that might try to exploit or abuse it. For example, I can ban an IP address from the site if they're uploading bad save files with the intent of crashing or hacking the site. So unless something suspicious (or blatantly malicious) is happening, I never even look at IPs, and no one but me has access to them.
I've run the save n play hosting service for over 8 years now. I created it in 2005 with the purpose of providing a quick and easy alternative to using sties like RapidShare and YouSendIt for uploading GTA save files, not for hacking some random peoples' IP addresses.
If you have any questions, feel free to ask me.