I believe the ringgit went down by too much in the first place because many Malaysians themselves overreacted by buying up other currencies. Now with the dollar going down, the ringgit can potentially appreciate very fast if the rush to convert back to the ringgit happens. But too fast an appreciation may not be good, so if needed, the central bank should sell the ringgit to slow down the appreciation.

BNM foreign reserves uptrend can mean BNM buying up foreign currencies by selling ringgit.

Don't have to be players coming back home. Just imagine what would happen to the dollar if China decides to cut its currency reserves by half.

One function of currency reserves is to be used to stabilize the local currency. If we don't bother about currency stability, then we don't need currency reserves. We can always let the market dictate its value.

All this while China has been on an export-led boom, so they had refused to let their currency rise too high, which resulted in the accumulation of huge currency reserves. But if their plan to reform their economy to consumption-led goes full-speed ahead, then logically they would let their yuan rise and they can easily do that by dumping their really, really huge dollar reserves. If that happens, the dollar can potentially becomes toilet paper.