The information is not specific to Sri Lankan. But our own company in the Uk will not permit their use based on advice received from the CAA. Perhaps the poster would be as well phoning the airline in question to ask the question.
In the Uk it seems that the CAA has suggested to airlines that reports suggests there is the potential for disturbance. It may be up to each operator to interpret the advice in light of their own operation. From your comment it seems to be the case in the US as well.
The latest fad to arrive seems to be mobile phones (cell phones) that have a "flight mode" this enables the phones functions to be used in flight whilst disabling the telecom function of the phone itself. The problem with this is that crew are unable to distinguish which phones are switched on and operating in this mode. The company has taken the view that it will not permit phones to be operated in flight at all that includes phones that may be operating with this mode enabled.