Wow. I happen to be fairly busy and I guess I missed that rule change.
The one thing that tends to keep a Modified format "happy" for players is that when their old cards are reprinted, they can use them again. It basically emphasizes that a rotating format is to protect the integrity of the game... and not a money making scheme.
Simply put, it seems like some reprint has vastly altered wording. Didn't Potion switch from remove 2 damage counters to remove up to 2 damage counters or vice versa? The creation of the largely vestigial 2-on-2 format means many cards can be justified as needing "significant changes" when they are reprinted.
Pokemon is a TCG. It is confusing to new players. Period. When I started, I thought you had to discard Energy upon attacking (making cards that only had to discard 1 Energy like Charmeleon look like bargains) and I mistook Double Colorless Energy as a Trainer (the colorling looked like a Trainer and since it was the only Special Energy at the time...). Both mistakes were silly and my fault. Not like knowing the differences between new and reprinted cards, right?
Wrong.
First, and foremost, a player has to be playing in some "official" capacity for this to apply. That means they either should know or need to be taught to check for errata. It is an inherent part to TCGs (the alternative , to "play as is" ends up being more trouble than its worth). So if we don't expect players (even young players) to keep up to date on this, what next? Clarifying an errata is often more apparent than realizing the need for a ruling on a card. If you play an old version and insist on using the old text, and I say its been errata'd (or vice versa), that's a clear reason to flag down a judge, who should know. On the other hand, think of all the card interactions that you really have to know the rule to easily understand and have nothing to due with errata.
My time is short, so I'll get to the point. The whole thing seems silly. All players wishing to participate in official TCG events should be required to have knowledge of the game that encompasses a) the fundamental rules, and b) errata. Judges are there to help when things aren't clear cut, or when there is confusion. Given the nature of this problem, it'd be more logical to require a judge read over or merely hand out a list containing all recent errata.
In all honesty, they've created a more complicated situation. Tell me, what is harder to explain to someone:
"Some cards were printed incorrectly. You need to visit the official website to get the errata.
You can use previous printings of cards in Modified if the card has been reprinted in a Modified legal set or as a Modified Legal promo. If the wording has been altered, treat all older copies as having the newest wording."
vs.
"Some cards were printed incorrectly. You need to visit the official website to get the errata.
You can use previous printings of cards in Modified if the card has been reprinted in a Modified legal set or as a Modified Legal promo.
If a card has been errata'd or the text otherwise changed a significant amount and it is then reprinted and the reprint has the correct text, you must then use the most recent, correct text version."
I can understand requiring players have a print out/corrected version in the local language, like we do for foreign language cards, but seriously: this complicates the game further and makes me feel like I am talking Yu-Gi-Oh, not Pokemon (they hire some ex-Konami staff or something at PUI?).