By using the second decimal to indicate both a rating "area" and whether to rate positively or negatively (and putting the negatives after the positives in order to make it more expensive to rate negatively) then the CRC modulus can be extended to 6 digits (so now only 1 in a million chance of a "birthday" clash).
+1 for area 1 (General)
0.01[123456] where [123456] = ( mod( crc32( 1dest ), 1000000 ) / 100000000 )
+1 for area 2 (Service)
0.02[123456]
+1 for area 3 (Quality)
0.03[123456]
+1 for area 4 (Privacy)
0.04[123456]
-1 for area 1 (General)
0.05[123456]
-1 for area 2 (Service)
0.06[123456]
-1 for area 3 (Quality)
0.07[123456]
-1 for area 4 (Privacy)
0.08[123456]
Although this could be useful over Bitcoin itself I am now beginning to think some sort of alt-chain might actually be preferable to accomplish this idea as then far more information could be stored with each tx.