superspawning or substrate to substrate work is dicey in the best circumstances. However, good sterile teqnique when going from sterile substrate to sterile substrate is almost as good as a flow rig.
pasteurized to pasteurized is a crap shoot that I only do in the wild. Wood lovers are a prime example, colonized wood chips can be placed in new banks quite easily.
but if one is serious, they should have a good pressure cooker and a laminar air flow hood. The hood forgives many mistakes.
except one. Exposed sporulating contamination up wind of the sterile work.
that situation will invariably ruin your work, your room possibly your house, perhaps your health.
there are situations where nothing else will do but still air in a glove box.