Q: Are there any problems that might confront the contractor subsequent to opting in or opting out?
A: If the opt out is provided after “introduction or supply” [of the work-seeker] it is not valid. It will only apply in respect of subsequent (new) contracts. In my experience, few agencies arrange for an opt-out to be signed before an introduction to the client - so many opt outs are worthless and the Regulations apply. Often however this is a problem for the agency and of benefit to the contractor.