Sorry for the double post.
I've just checked my original game card. (I legally own SoulSilver, however I play it on a flash card) And much to my surprise, the load game text on my original card is red too! Of course I haven't used Pokesav on my original card. So I've been wondering, why is it red too?
Then I remembered something. I did transfer a single Furret to that game. That Furret was hacked with Pokesav. Does the game detect illegal Pokémon, no matter in which way it was acquired, and then turn the text red? Maybe it does. I can't think of anything else.
If that's true, then that's a bit unfair. Let's say I wouldn't want to have any hacked Pokémon, completely hypothetically speaking. I could easily trade with some stranger without knowing his Pokémon is hacked. And then I have to suffer the consequences for receiving a hacked Pokémon I don't even want!