That shouldn't even be possible. I guess if the float needle valve were completely open it might. The Rebel carb has an overflow pipe, and fuel will run out of that before it runs into the engine. But it is a small overflow, and likely wouldn't have the capacity to let all the gas out from a fully open needle valve. I drain my carbs once in a while, and fill them with pure Seafoam. I use the carb vent hose, which allows you to get more in than the fuel line. I pour it very slowly, and stop when it starts dripping from the overflow. That must have been some awfully thin oil.
2016 Rebel, 2013 Royal Enfield B5, 2009 Genuine Stella, 2006 H-D Sportster 1200, 2006 Vespa GT200, 2001 Yamaha XT225
"I refuse to believe in a risk free society where the thrill of living is traded for the safety of existence." ó Nick Ienatsch