pre-segwit nodes think that segwit inputs are "anyone can spend" utxos,
What I never got about this, wouldn't pre-segwit wallets then not think they can spend it too? So if I understand this correctly (which I probably don't), then every segwit transaction should increase the balance of every wallet unaware of segwit since they are marked as "anyone can spend".
Oh, wow... Classic, immediately after posting the comment, I read it again and now I see, it's about inputs, not UTXOs.
That should answer my question.