anyone seen this?

alright well the other day i was talking to a guy about helping me with my bags( plumbing and wiring) he said he would help me. well i looked at his truck and wasn't sure about it, the way his was setup was like this, line from his tank went directly to a valve, then t'd from there and ran to his bags, so he was running on valve for the front and one valve to the rear. anyone ever done this? it was hellaaaaa slow too. just curious, never seen it before