Actually I find your assumptions biased or just plain ignorant.
On the tongue: involves breathing on the priests hand, a venue for spreading disease—this is unavoidable.
And certainly over 100 people or more, the risk of someone waddling their head and tongue at an innoportune moment brings the moment or mistake of the priest touching the tongue of the receiver.
Breathing on the priests hand, or accidently having your tongue touched by the priest, is a communicable disease risk for those later in the communion line. Much higher risk than over simple communion in the hand. Although both
bear risk.
This is common sense thinking and not biased. Or you could say I am biased towards avoiding communicable disease because this is where my thinking derives from. Whereas it would seem your bias is one in favor of COTT(Communion on the Tongue).
I personally receive in either fashion, depending upon who is doing the administering.
Most people with their mouth open, tongue out and head tilted back are probably holding their breath (at least I do).
Mistakes certainly happen (moving the head, closing the mouth, etc.) but hand touching hand when you don't know where those hands have been is probably not a good idea either.
I would think that the best way to avoid problems would be to receive the Host only, rather than the Precious Blood as well. Even with fortified wine and wiping and turning the chalice, that is probably a higher risk.