I remember dubs "Americanizing" anime, changing all of the cultural stuff around so that it would make more sense to the average American. I also remember Azumanga Daioh's dub being butchered in a similar manner.
"Making sense" = "butchered"? Really? I don't think Azumanga's dub rewriting jokes about "bean knowledge" as "grains of truth" is quite the same as (or even "similar" to) calling riceballs doughnuts, changing character names, digitally editing the video to erase "Japaneseness", or pretending the show takes place in America. And if you think ADV didn't care about educating people on cultural aspects of the original material, check out the
liner notes I scanned.
Triltaison's already made many of the relevant points -- straight-out cultural whitewashing is limited to kiddie/mass-broadcast products, and dubtitles are rare. (In fact, I'd say these days the bigger problem is dub scripts that are rushed, poorly-adapted readings of the subtitle scripts, but that's another issue.) Generally speaking, you can expect official subs to be more localized than the average fansub, but less localized than the dubs they sometimes accompany. In most cases, this means:
* Honorifics dropped or adapted
* Sibling terms translated or changed to <name>
* Sensei and the like translated to forms of address English speakers might use
* Western name order used for full names, though the use of "family-name-only" address is almost always kept
* Depending on the company, food terms and fan-culture loanwords (like moe, otaku, anime, manga, tsundere, etc.) can be left in Japanese.
So in a way, they're not unlike fansubbers like gg and Commie, except that official subs don't have all the "herp a derp u mad cool story bro" stuff or other blatant joke rewrites. But again, these are generalities -- some official subs, especially by Viz, are more localized. Others, such as many from everyone's favorite whipping boy Funimation, are less localized and use things like honorifics, untranslated sibling terms, and Eastern name order.