I am curious about the tactics that someone would use if they wanted to obtain the maximum possible total credit limit. I don't actually intent to do this, but I'm just curious about how much money someone could make via arbitrage. For example, would it make sense to lower the limits on your credit cards so that you could obtain more, then raise the limits again? Does applying for credit cards all at once still work, or have they updated their systems to be able to realise when someone is doing this? Are there any other tricks that could work?
If you lower your limits, you could also lower your score. Lowering your limits will raise your utilization rate.
But if you did try it, your gain might only be temporary. They could decide to lower your limits if they discovered you have more cards than they realized.
You are expecting perfect knowledge, so that a new card realizes you can handle more credit. But you are also counting on imperfect knowledge, so that they won't notice when you raise the limits on all your cards.