A lot of the [scams] questions involve a reversible deposit followed by a non-reversible withdrawal.
A common method is a bouncing check that can take over a month to bounce.
As the recipient of a deposit that might be invalid, is there a way to request that you back confirm or certify the deposit? Alternatively, can you ask them to ringfence the funds until they are confirmed?
This is a hypothetical situation for me, but it seems there are others who might benefit from knowing whether this is possible.