Ideally, a combination of neutral, non-commanding low threat terminology used within the media would be best, e.g. “If you do not want to donate your organs, you can always choose to opt-out”. However, as you say, the media often use sensationalist high threat messaging.
There is some evidence that a few specific messaging strategies can mitigate reactance.
The first, restoration postscript messaging, is designed to mitigate reactance by reaffirming the reader’s autonomy after exposure to a freedom threatening message. For example, explicitly stating “Organ donation remains a personal choice”. The second, inoculation messaging, forewarns the reader of a potential perception of threat to freedom as a way of decreasing the likelihood of negative reactant responses. Both methods have had variable success across health communication literature, including campaigns designed to decrease alcohol consumption and increase physical activity however, no research has assessed these strategies for opt-out consent.
Aside from direct messaging techniques…
A number of participants within the qualitative interviews I conducted also felt that recording an opt-out decision would be purposely prohibitive: “they will make it as awkward as possible to opt-out in my opinion”. Expecting these difficulties when trying to opt-out arguably may contribute towards perceptions of coercion and may increase perceptions of threat to freedom. So, a relatively simple way of minimising this would be to ensure the pathway for registering an opt-out decision is very clearly communicated, and the opportunity to register an opt-out decision as straightforward and accessible as possible. While this sounds very simple, quite often only registration is promoted. Now that the UK has moved to opt-out, it’s vital that where appropriate, we communicate both.