You're quite right that the rules are clear and native speakers get them correct almost all of the time (I've not seen one get it wrong while speaking but some people were taught it as a spelling rule at school and so tend to write it incorrectly), but the difference is that different speakers pronounce the leading "H" differently.
In Australia we pronounce the H more like "heitch" while in the US people tend to pronounce it as "eytch" (IPA would probably more descriptive here, sorry!). In the UK it's a bit more of a mixed bag, as others have already elucidated.
"Ambiguous" was probably a poor word choice, I meant to say that because both ways of writing are technically valid based on the accent of the author there is an element of freedom in the choice that tells you something about them.
In Australia we pronounce the H more like "heitch" while in the US people tend to pronounce it as "eytch" (IPA would probably more descriptive here, sorry!). In the UK it's a bit more of a mixed bag, as others have already elucidated.
"Ambiguous" was probably a poor word choice, I meant to say that because both ways of writing are technically valid based on the accent of the author there is an element of freedom in the choice that tells you something about them.