Shorn of their frivolous elements (but with their original boldfacings), examples 1-4
- I did not allow them to deflect me.
- It brought home to me the whole incident.
- Miss Hemmings was looking up at me.
- I introduced myself to you.
represent several different kinds of construction, and the various prepositions are variously governed by the construction or the predicate.
The to appearing in ditransitive sentences marking the receiver of the trajector
(usually the trajector is the direct object) is governed by and participates in the Dative Alternation:
- She sent/gave/donated/paid me $45.00 ~ She sent/gave/donated/paid $45.00 to me.
Some people have wanted to call one of these me's -- but not the other -- The Indirect Object.
However, there is no agreement as to which one is the true, the blushful Indirect Object, since some say the one without the preposition is it, while others claim it's the one with the preposition.
And then there is for, which is a benefactive construction representing someone who benefits, and can be attached optionally to any volitional activity sentence.
- I held the door open (for him).
- I fixed his car (for him).
- I dug a clam (for him).
This can masquerade as an indirect object, provided that the object of benefactive for actually does receive the trajector, in which case it can undergo Dative Alternation just like to:
but if not, then for phrases doesn't undergo Dative:
But none of the examples above are ditransitive predicates.
(1) Allow NP to VP is a normal infinitive complement clause with the infinitive complementizer to (which is a preposition in the same sense that the is an adjective). Allow here could either be a B-Raising predicate -- where the subject of the infinitive becomes an object in the upstairs clause, even if it doesn't belong there, as in She did not allow the shit to hit the fan; or a B-Equi construction -- where the subject of the infinitive plays an actual role as patient or recipient of the main verb, as in I did not allow him to move an inch.
(2) Bring home to is an idiomatic predicate that means 'deeply and permanently impress'.
Bring home to is a unit and can't be split; to and home is part of the idiom. Home is not a direct object of bring, for instance; it can't be passivized -- This brought it all home to me is fine, but not *Home was brought it all to me by this. The actual object of bring home to is the experiencer, but a to-experiencer phrase is not obligatory with this idiom. One can simply say This just brings home how important it is, with the usual indefinite experiencer unmentioned.
(3) Looking up at NP is the same preposition construction as looking at -- i.e, an arbitrarily-governed transitivizing preposition at governed by look, with the added wrinkle that of a directional component. This is not the phrasal verb look up, of look up the word/look it up, but the straightforward directional 'look up the stairway/look up it'.
(4) Introduce NP₁ to NP₂ is a reciprocal construction that governs the preposition to, even though one always introduces individuals simultaneously (there are different conditions in introducing an individual to a group, and other contexts) so that, if I introduce NP₁ to NP₂, then I have also effectively introduced NP₂ to NP₁. Thus the directionality sense of to is not involved with _introduce X to Y, just like the grid location sense of at is not invoked by the construction look at X.
Executive summary: Prepositions have complex instantiations, and may or may not mean anything.