Not to get too far into the weeds on this, but the Anderson transaction doesn't imply that these are revocable waivers (which did indeed go away with the second trade deadline, as far as I know.)
The way I understand it (which is probably incomplete), under the old rules with waiver trades, a team could pull its player back from waivers even if another team claimed him. So a team placing a claim was trying to claim the right to negotiate a trade. With the old rules, if the Angels put Anderson on a revocable waiver and (let's say) the Reds won the claim, if they didn't offer a trade the Angels wanted, they would simply pull Anderson off the waiver and keep him. This is why teams put a lot of players on the old revocable waivers, because they could gauge potential trades and there was no risk of losing players for nothing.
So I think the actual current situation with Anderson is an option the Angels had when he cleared a different kind of waiver. On an outright waiver, a team could have claimed him and would owe only his salary for the rest of the year. If no one claims a player on outright, the original team theoretically has the right to keep him in the organization without giving him a 40-man roster spot, except that Anderson should have had enough service time to reject an assignment to the minors.
So assuming he cleared outright waivers, the Angels probably knew he would choose free agency and they'd still owe the rest of his salary, so they just kept him and re-committed the roster spot to him. I'm pretty sure that's a way that a player can be waived and not change teams.