There have been a couple of different suggestions to give a penalty to a driver who initiates a track call.
The simplest IMO is to delay the track call by X seconds. The gives the other drivers a few seconds to continue racing.
This is implemented in SSDC
For casual racing, without a marshal, this is preferable to a stop/go penalty because
1) a pit lane may not be available
2) drivers may not realise they have a penalty, since they are not looking at the screen