It may be interesting to know that for example orthopaedic surgeons cannot come to a consensus view on whether DVT prophylaxis is of benefit following surgery, even though there is a proven increased risk of DVT associated with surgery.
The final point therefore is even assuming liability can be established ( and personally I think this unlikely) the final link in the chain of causation would have to be that the claimant could demonstrate that if the "calf exercises" now being advocated had been employed, that the risk of DVT would have been significantly reduced.
Since the evidence is far from clear cut in surgery, even where more invasive prophylaxis with injectable anticoagulants is concerned, it is unlikely that significant benefit could be proved for calf exercises by the claimant.
The only other way that this final hurdle might be overcome would be if the claimant could prove (on the balance of probability) that had they been told they would that had they known of the small risk they would have avoided flying.
What would be the likely outcome of all of this if liability could be established?
The majority of DVTs occur silently, in other words they do not give rise to any signs or symptoms, but can be detected using ultrasonography or plethysmography. Only a small number give rise to calf pain and swelling, and only a very small number go on to pulmonary embolus and death.
The "damage" to an individual is therefore relatively minor in most cases , and in a few unfortunates who die, the compensation is relatively low compared to settlements where diasability has to be compensated.
One final point, if liability were to be established on the basis of the general principle that stasis increases risk of DVT, it might be argued that the government through its public health doctors might be vicariously liable not only for air travel, but also for other longdistance cramped methods of coneyance, maybe even the car!