Reddit stores the IP you use for registration, login, upvote, comment etc... That's why a lot of times when people buy aged accounts and use either a proxy from another location or a low quality proxy, they get banned right away. There's also never a guarantee that the vendor you're buying from used a proper script and high quality proxy when creating the accounts. Almost all the Reddit accounts I've bought in the past end up with a bad CQS score because of these factors so my theory is that it is better to create your own accounts by hand rather than buying aged accounts