How ideal are smudge pots for frost protection?

I have deliberately chosen smudge pots (not to be confused with return stack burners) as the first frost protection method to be evaluated as they have some aspects of operation that are controversial (like being so bad that even local body Councils have banned their use).

How do they feature?

The Grower:

• It should be cost effective to install and run.                                  Very Cost effective
  
• It must be reliable.                                                                       The mechanism is simple, so failures are unlikely.
  
• It must protect the crop from frost.                                               Effective protection.
  
• It should not be labour intensive.                                                  There is a medium to high requirement for attention during operation
  
• It must be safe to operate.                                                           Probably about medium
  

The Crop:

• It must not affect the normal growth / development of the plant.   No problem
  
• It should not introduce any foreign contaminants.                          Probably a low to medium risk here.
  
• The quality of the fruit should be unchanged.                                Probably low to medium again
  

The Environment:

• It should not deplete a natural resource.                                      It burnt oxygen, but this hasn't been identified yet as a resource depletion issue.
  
• It should not make any physical impact other than on the crop.    The physical impact was high with huge palls of smoke covering large areas and soot accompanying it.
  
• It should not introduce any pollutant to the environment.             Very high with considerable pollutants released into the atmosphere.
  

The Neighbour:

• Its operation mustn’t affect their health.                                   Medium risk with smoke pollution exposure
  
• Its operation shouldn’t degrade their property values.                Property values relatively unaffected unless it was during a frost season (so low)
  
• It shouldn’t degrade their enjoyment of their own property.        During times of use, enjoyment would drop considerably.
  

What can we read from this?

Well with features that were important to the grower and relatively benign affect on the crop, the technique was popular in the day. In spite of a significant impact on the environment and neighbours. However as consciousness was raised to the health risks and pollution impact, regulations were enacted to limit, prevent or alter the activity.Parallels can be drawn with frost fans in the sense that what little regulations are in place are not well structured or not followed and this has allowed the wild west mentality to take hold. Now as the impact of the devices has begun to be felt by more and more people, their use is being viewed less favorably.