This is true, and when people talk about recycling aluminium cans they’re actually only talking about recycling the aluminium in those cans. The liner is not recycled.

However it’s a relatively small amount of plastic, and burning it while melting the metal does prevent it from ending up as plastic pollution. So aluminium cans are still better than non-recycled plastic packaging.

FYI messing with communicating infrastructure, such as by jamming phone signals, is highly illegal and most networks are actively being monitored for disturbances.