Pete is quite right in my opinion, 2.4GHz may offer a greater reliability for reception but that does not mean it is safer. It may offer greater security against that plane flying off into the distance out of control but any reliance to safe guard personal protection by the use of 2.4GHz is dangerous. When the bot is armed, you keep clear as any hobby radio system can malfunction and cause an unexpected response. Having spent many years specifying safety related equipment for use in industry to IEC61508 and assessing equipment to safety integrity levels (SIL) to reduce the risk of injury to personnel, I can assure you that 2.4GHz hobby radios will not even meet the minimum of safety requirements.