We took the decision to switch to yellow hose from clear/black hose well over a year ago now. This was following a legal situation with one of our clients, interestingly there have been several more since then and one that we specifically know of currently. The FED were also interested and contacted us to find out more - they have since been in communication with the client involved.
It is not strictly speaking a H&S issue as the HSE have not specifically 'come down' on this issue - however using clear or black hose would go against their standard advice as it is in itself a hazard that has been placed in the way and is difficult to see for those not looking and those of restricted vision. On the grounds of a client's private property there really would not be an issue as the client has requested the work done and would share the responsibility for any hazard subsequently introduced to their property - unless it was over the front path as the public has a legal right to call at a homes front door. However wherever work is carried out over public highways, pavement and communal access areas/grounds then it would become a matter involving the general public.
In H&S terms you should try and remove/reduce the risk first. The first step should be to try and avoid running unnecessary hose across public areas -perhaps by parking in a different place etc. The second step if you cannot remove/reduce the risk is to help identify the hazard to others - using yellow hose helps to fulfil this H&S responsibility. Yellow hose will not remove or reduce the risk at all, but it will help identify the hazard to those around.
This is really either a 'caring' issue or a 'litigation' issue:
1.Either you as an operator 'care' about reducing the risk to people around you. Seeing an old lady's face completely smashed up is apparently not nice for a window cleaner (or the old lady).
2. Or you as an operator do not want to be 'litigated' against - this could be expensive and very stressful, your insurance of £1,000,000 may well not cover it.
Yellow hose is actually much harder & expensive to source, as we have to have it made to order whereas clear hose is available from almost all hose suppliers and at more competitive prices. We are happy now that we are not supplying equipment that would put a window cleaner in a position of unknowingly placing others in greater danger. Of course if a window cleaner wants to replace the hose with clear etc that is their decision that they knowingly are taking and as such we leave that with them - it's a free world after all.