Running any vehicle with a low amount of fuel in the tank has risks of rust/sludge or fuel tank debris being sucked into the fuel system & then causing problems with engine running or poor performance due to reduced flow of fuel to the engine.

With modern vehicles the risk is significantly higher due to the tolerances that these modern vehicles fuel systems run at & the high technology that is now found in modern vehicles fuel injection systems.

Regular servicing of the vehicle including fuel & air filters will assist in the reduction of possible poor running of the engine, which in turn will increase fuel running costs & consumption, regular servicing will also help the garage to identify any other possible defects with the vehicle that left un-repaired would end up costing the vehicle owner more in the long run for full replacement of the vehicles fuel injection system.

A more in-depth article on fuel injection can be found on wiki by following this link>> Fuel Injection