This picture (below) is the suction line I use to remove the wrong fuel. this was taken when doing a job that had 50 litres of petrol in a diesel mini, this was being taken from the fuel tank as the car had not been started. this hose is full of fuel, about 70% petrol, and 30% diesel.
This is a picture of the same hose, the car was a Diesel VW Polo, it has been fill’d with 90% petrol, and 10% diesel, the car had been left overnight after loosing power and being towed back to the customers house, the suction line was attached to the high pressure pump inlet, as you can see the fuel has gone black, this is becuase the petrol has desolved rubber in the fuel lines, this car sat for a day with a very strong mix of petrol, it had also been driven until failure, the dark colour is a mix of rubber and plastic that has dissolved in petrol (fuel hoses are made type specific to reduce costs for car manufacturers,i,e diesel for diesel hoses only and petrol in petrol hoses only), I would not expect this to have done the car any real harm over an 18 hour period, just a microscopic layer of fuel line has been stripped off from the inside, these lines are fairly thick so a short bit of contamination once is fine, if you do want to make a habit of misfuelling regularly and leaving the car sitting for days with the wrong fuel in it you will eventually need new fuel lines. and plastic fuel components.