Doug refers to air being compressed in the tank making room for a pint (1/2 liter) of fuel. He also refers to a bladder, which should prevent air from entering the fuel lines.
You can see from the picture that it appears to be a Parker Bladder Accumulator which was designed for hydraulic applications. So the tank fills with fuel, the bladder is filled with nitrogen, which compresses as the pressure rises, effectively adding capacitance to the system.
From reviewing parker's product lineup, my primary concerns would be temperature and material compatibility for the bladder/seals.
https://www.hydraulicspneumatics.co...tors/Article/False/6446/TechZone-Accumulators
In theory, it's not a terrible idea if you design the system appropriately.