for example if you are sitting in a light single at 2,500' in icing conditions with an MSA of 2,400' and you get a pirep that the cloud base is 2,350' what is the safer option?
Hopefully you would be sat in your arm chair at home having carefully studied the weather forecast and realised that the forecast conditions were not suitable for your aircraft/qualifications.
1000 feet should be fairly safe, much below that you can find oil rigs and wind turbines.
But are you sure of your QNH ?
I flew maritime patrol for a living with a previous company. We would not decend below an absolute minimum of 1300ft on the forecast regional QNH if we had not become VMC as obstacles could be up to 299ft without being shown on a chart.