Any electrical or electronic circuit that has a changing current level WILL transmit radio waves. This is Faraday's law in action. If you're ever listening to AM radio and switch on a light, or especially something like a motor, you will hear a pop or static from the radio. That's because the radio has picked up the radio wave transmitted by the light/motor circuit.
Similarly, any electrical or electronic circuit WILL pick up any radio waves the pass through it. That is, the radio waves will induce currents in the circuit.
The only questions are, how strong are the radio waves transmitted from a circuit in question, and how sensitive is the circuit that receives the radio wave.
Naturally, radios, including the handhelds you asked about, are prone to both transmission and reception of radio waves because that is exactly what they are designed to do.
This is the reason airlines ask you to turn off certain equipment during critical periods of flight, notably during takeoff and landing.
