alkene reacts with bromine water in dark place?

Bromine reacts with an alkene because the bromine adds on across the double bond to form the dibromo alkane.
This reaction is spontaneous and does not require activation by light, etc. Hence it will occur even away from light ( in dark place). Many reactions betweem hydrocarbons and halogens, particularly substitution reactions between alkanes and halogens require activation by light to occur.
This is the reason for the statement: " alkene reacts with bromine water in dark place".

What? I thought bromine just reacts with alkenes and thats that. Whats with dark place? Does it make a difference? Unless the that day is just soo sunny and it affects the reaction.....