Earlier quoted context omitted.
That's elegant. So, OP, I have to know: did you come up with the synced seed first and then try to build an idea around it, or did the idea of simultaneous, server-less, auto-generated endearments drive you to this solution?
I had the gift idea for my girlfriend a few years ago. How to implement it came next (even so the tricky part was how to sync the seed)
Do you do some sort of seed exchange/negotiation? Something like swap current system times, and use the higher as the seed?