The only harm that can be done is that the assumption is wrong and they delay the release, if everything else is done correctly. It's simply a choice you need to make, not necessarily something the MR community should debate over.
Pretty sure they are jailbreaking 4.1, so you could probably do it. Im running 4.1 so hopefully it will At this point I think its the bootrom exploit working its magic so OS version doesnt matter up to 4.1.