The concern lies in a scenario where miners might signal for these changes before the majority of users have upgraded their systems to support the new rules. Such premature signaling could lead to a network split, which would be detrimental to the stability and security of the system. The language suggests that there is an element of uncertainty in relying on the assumption that users will have their systems updated in time for any proposed activation. It underscores the importance of ensuring widespread user readiness before miners proceed with signaling to avoid the possibility of fracturing the network.