I don't really like cracking the fuel injector lines because the fuel pump will purge out the air anyways. It's suggested to counterhold the injector body when you crack open the fuel injector hard lines too. I don't see how cracking the fuel injector lines is any different from removing the return fuel line to the injector pump. Both will spray fuel everywhere and both are on the same return line.
A much cleaner solution is to apply vacuum to the return line so that it isn't spraying fuel out and you just need a mity-vac. If you're by yourself, you don't need a second person to quickly shut off the ignition once fuel is spraying everywhere.