Conditions may change, but your continued acceptance is not inferred from an earlier acceptance
When you're not logged in to a service, but use it repeatedly, it may still feel weird that their terms and conditions can change between one use and the next. However, this does not violate the rule-of-thumb that each new version should be accepted from scratch, without inferring your acceptance from the acceptance of an earlier version. Since no acceptance is inferred from continued use, but only from current use, we rate this as neutral instead of bad.