Real world hash table can either be resized to avoid worst-case degradation or else be provisioned to have a good amount of slack when the worst expected case occurs. (E.g. a hash table used a cache will apply pressure to evacuate old entries before it gets foo full.)

Bucket hashing obviously has no problem finding a free spot. I didn't say chained on purpose because chains can be resizable vectors, so we load at most one pointer when going from table to bucket.