Since permission for that Sabbath was once granted the permissibly continues until the conclusion of the day.
And a story:
Rab and Samuel were once sitting in a certain courtyard (on Shabbat) when a parting wall collapsed. ‘Take a cloak’, said Samuel to the people, ‘and spread it across (the gap).
He thus created a temporary partition. But, if the space suddenly became “public” with the collapsing wall, stretching the garment over the gap would not be permissible. Rab expresses his disapproval by “turning his face away.”
‘If Abba (Rab) objects’, Samuel told them, ‘take his girdle and tie with it’.
Whew! Guess he feels pretty strongly about his opinion. But, one can ask, why was this even necessary?
Now according to Samuel's view, what need was there for this, seeing that he ruled: ‘The tenants on either side may move their objects to the very foundation of the wall’? — Samuel did that merely for the sake of privacy.
If Rab, however, held that this was forbidden, why did he not say so to him? The place was under Samuel's jurisdiction. If so, why did he turn away his face? — In order that it might not be said that he held the same opinion as Samuel.