Often have many millis and centis and other insects living happily amongst substrate both for dragon vivariums and humidity trays for tropical plants. Have never batted an eyelid or shown any concern to these and let them carry on with their important roles, only when a particular guest has potential to bring or cause harm do I react. Ofcourse harm in terms of intro of harmful pathogens is a given but then systemics do there thing as intended, so enough space for harmony really.

Im a sucker for collecting and picking up various natural items such as fallen mosses, twigs with lichens, all purely for the aesthetic value of my personal hobby and so i learned my lesson from this contamination risk the hard way but i still continue to do it now but additional methods have been put in place as far as preventative treatment goes. Nepenthes are a great indicator of snail/ slug presence and those problematic threats from decaying orchid tissues or rotting bulbs are often isolated from spreading due to the work of these detritivores. They are great at maintaining the crown bases of cymbid plants. I would never recommend this kind of approach though due to the obvious controversy and debate, its more something ive become comfortable with, these mini eco systems are fascinating and not always a bad thing.