It is a very effective and cheap method of controlling a major pest that can badly affect rainbow trout.
When I first encountered the problem with rainbows I couldn't really understand it. It had been my understanding that it affected shoal fish like roach and bream, or more sedentary fish like pike. A chap doing his dissertation on Argulus told me he thought it likely that rainbows were also affected because being non-native they had no natural defence.
Whatever, the plastic tube idea is a great idea and well within the capabilities of any club ti implement.
I came across this method a few years ago. Just a matter of checking the tube for argulus/eggs, removing them and letting them dry out. Either put fresh tube back in or replace the tubes once argulus/eggs have died off and tubes cleaned.
Another tactic to use on a trout fishery is to reduce the potential host fish. So, if your club water has lots of roach, perch, or bream then they can be culled at least annually. If they are health checked and are clear of Cat 2 parasites then they are worth money which can be used to pay for your trout.