Biggest risk is the "significant other" may get annoyed with the time and money you spend and beat you over the head with a pan/rolling pin/etc.
Castor oil is a diuretic. Ever notice you have to visit the crapper more frequently after racing nitro? Enough castor oil fumes will give you the "squirts." No long-term risk though.
And you are stiff and sore from standing all day and running/bending/etc when marshalling. It is an unusual exercise (not in amount, but in the motions you do.)