A receiver contains an oscillator circuit. Theoretically, if this circuit isn't properly shielded, it can act as a transmitter and interfer with aircraft systems. Whether this is really a risk or not has been debated a lot in various forums recently without any clear conclusions so it is possible. The behaviour of electromagnetic radiation in a metal tube such as an aircraft fuselage appears to be rather hard to predict, with nodes forming in unexpected points. If in doubt, ask the cabin crew. That way, they'll know where to look for the cause of any irregular indications.
I thought I was doing good trying to avoid those airport hotels... and look at me now.