Two years ago, Royal London refused a pension transfer due to concerns about the status of the receiving scheme and the client's right to transfer the pension into it.
The client contested the decision by complaining to the Pensions Ombudsman who found in favour of Royal London.
However Royal London's decision was later dismissed by the High Court after the client appealed.
According to Kate Smith, head of pensions at Aegon, the creation of a closed watch list of those who may be involved in pension scams sounds like a good idea "on the surface".
She said: "In reality though, it should only be used as part of a range of procedures to protect members' pensions."
Scams are constantly evolving and an over reliance on a watch list could provide a false confidence that everything possible was being done to combat scams, she added.
There is also the issue of keeping the list up to date, Ms Smith said.
She said: "Rather than relying on someone else to spot the signs, all pension schemes and firms need to remain vigilant against fraudulent activity."
Darren Cooke, chartered financial planner at Derbyshire-based Red Circle Financial Planning, who launched a petition to the government to ban cold calling, argued that the watch list is a good idea to help schemes and providers be aware of potential issues.
He said: "The new legislation promised by HM Treasury includes the option for providers and schemes to block transfers if they suspect a problem so this will be extremely useful then.
"They will need to be careful though as to the criteria for including a firm/IFA or investment on the list, but anyone who is legitimate should have nothing to fear."
According to a policy paper published in September, stricter legislation to stop scammers operating fraudulent pension schemes will come into effect in 6 April 2018.
Under the new supervision regime, HMRC will have the ability to refuse to register, and to de-register pension schemes, which will also include master trusts that do not have authorisation from The Pensions Regulator.