Let's clear this up:
This is not a bandwagon thing.
While handling a snake causes some stress in general, pinning is extremely stressful for the animal. It is also potentially harmful to the snake and dangerous for the handler.
There is no need to pin a venomous snake in the field. If you need to get a closer look or to gather data, then the best method is to use tubes to restrain them (and protect you).
Period.