Reference cases for reosonable man:
Blyth v Birmingham , fire plug had burst and flooded the claiment's house. The claiment argued that Birmigham should've done more to prevent this.
Held - there's nothing they could have done , the extreme weather was unpredictable too.
Hall v Brooklands Auto-racing club racing cars had a collision , and flew and had killled two spectators and injured a few. One sued and argued that D had not taken enough precautions to prevent such thing from hapeing.
Held - not liable , because they could not have reasonably foreseen this issue as in their 20 yr business , no such thing had ever happened. The reosonable man in this case wouldn't have done anymore or less than what D had done , because they wouldn't have needed to as nothing like that had happeed before.