What experiences have people had with the Non-Immigrant O visa regarding children's entry to Thailand?

Okay keep in mind that just because there is no overstay fine for children under 15 and no banning for children under 18 that is not the same as saying they "don't need a visa to be here"

There was just a recent case where a foreigner was flying back in to thailand on a valid visa and their young (8 y/o) child was coming back in with them on a 'free stamp' (visa exempt entry).

They were pulled aside by passport control questioned as to why the child didn't have a valid visa AND the child only got into the country because the parent was able to contact their employer who assured immigrations that they would apply for a "piggy back" Non-O visa for the child (family member of a foreigner who legally works here)..

So whether you can or can't get a child in free stamp if you're on a Non-O visa seems to come down to the officer you're in front of at passport control

remember once a child hits 15 and overstays while they still can't be banned (that happens only when they turn 18) they can be fined for overstay @ 500 baht a day like everyone else