“There is no principle for coating spores.”
Apparently the rest of the world sees it differently than you:
American Medical Association:
http://www.ama-assn.org/ama/pub/category/print/6631.html\
Spores can also be COATED with an electrostatic powder so that they do not clump easily and fall to the ground quickly; these spores would then be more easily aerosolized (dispersed into the air).
Christopher Grace, MD (Univ of Vermont):
http://www.fahc.org/Healthcare_Providers/Healthcare_Providers_Contribution/Bioterrorism_Curriculum/Email_4_April_14.pdf
Anthrax spores that have been weaponized are finley milled to <5um diameter and COATED to prevent clumping.
Alan Zelicoff:
http://www.ratical.org/ratville/JFK/JohnJudge/linkscopy/3nations.html
``The amount of energy needed to disperse the spores [by merely opening an envelope] was trivial, which is virtually diagnostic of achieving the appropriate coating.’’
EDVOTEK (The Biology of Baterial Sporation):
http://www.edvotek.com/pdfs/161.pdf
The spores may also be COATED or mixed with silica.................
DuPont presonal prtotection (technical bulletin):
http://personalprotection.dupont.ca/pa_pdf/h96406techanthrax.pdf
Inhalation exposure is enhanced when anthrax spores are artificially COATED to reduce clumping.
Coulmbia University:
http://www.columbia.edu/cu/biology/courses/g4158/presentations/2004/BacillusAnthracis.ppt
Weaponizing anthrax: Basic approach is to COAT the spores with a fine silica.
http://www.forensicnetbase.com/books/2786/1660_09.pdf
Further “weaponization” can be accomplished by processing of the spores such that the tendency for individual spores to clump together is reduced and penetration deep into the distal airways is facilitated. This process results in a detectable COATING of the spore that was seen in oragnisms recovered during the 2001 attack.
Not "the rest of the world." Just some people who believed what they read in the media.