Totally agree with the above post, a sad lesson can be learnt from reading the AAIB report for the crash of N90AG at Birmingham in 2002. Part of the report says:
During the morning, other witnesses stated that they had seen frost or ice on the wing surfaces of N90AG prior to departure.
Other aircraft, which had been parked overnight, were de-iced during the morning, with associated reports of moderate to severe ice or frost accumulations. Neither crew member requested de-icing, so N90AG was not de-iced prior to departure.
Sadly 5 people died due to the surfaces not being cleared.