Note that in some cases a counterparty could be considered an "advisor" or "promoter". This could be the case if a counterparty participates in structuring a transaction, or even if the counterparty merely provides assistance in implementing a transaction. If so, confidentiality provisions in agreements between counterparties could satisfy the confidentiality hallmark and contractual representations and indemnities as to taxes could satisfy the contractual protection hallmark.
Reporting each transaction in a series may require reporting over multiple taxation years, and it may be quite difficult to determine all transactions that are part of a series of transactions that include an avoidance transaction.