Today’s paint on all cars is thermoset which means it will always remain in a permanent solid state. So the new paint can’t be melted into the old paint. All automotive & paint manufactures do not recommend that repair shops attempt to melt or burn in the clear.
Soft edge tape, reverse masking or hard line masking are 3 short cuts insurance company try to force shops to use as it reduces the claims cost. When they customer is not happy with the end result they will blame it on the repair shop.
Keep in mind insurance companies are not the ones repairing the car so they will never assume any liability in writing when you are not happy or if there is issues with the repair.