Given that Satoshi's coins are in Pay to public key outputs, the pubkeys are publicly available already. So if we assume Satoshi is dead or otherwise gone, his coins moving would actually be an indication that Quantum computers exist because the only way for them to move (assuming he is no longer around) is for someone to have been able to compute the private keys to those exposed public keys, presumably via quantum computer. In general, it would mean that the ECDLP is has been broken in some way (regardless of QCs) and should no longer be relied upon (i.e. we should move off of ECDSA and Schnorr).