We've had men and women as grossly obese as this, giving major equipment fitting problems, tho' fortunately Pedro's scenarion hasn't arisen. Someone started a similar thread on Scubaboard recently but from the other perspective - an over-weight person complaining of being discriminated against. The bottom line is that if we couldn't help someone in these circumstances we would be irresponsible taking them out. We probably would, though, as no-one wants to be publicised as "the operator that only deals with thin people". A very tricky one.
P1 - what brought this up?