This seems like a correct answer. The company (1) wants to be seen as the sort of company that helps charities, (2) doesn't care deeply about the charities, and (3) wants to motivate employees.
The first part explains why they have a budget for charities, and the second and third part together explain why they let employees allocate that budget instead of the company doing it itself. The charitable explanation of the second part is that the company trusts their employees to have good knowledge about charities, and thus kinda outsources the research of good charities to them.
On the other hand, an uncharitable explanation is that if most employees don't donate to charities, then this strategy allows the company to appear more generous than it actually is. For example, if a company with 1000 employees publicly declares to match each employee's donations up to $1000, it gives an impression as if they are going to donate $1000000 to charities, while in fact they may know that only five of their employees actually donate to charities, so the expected expense is $5000. (There is a risk this could backfire, but maybe they did experiments with smaller sums in the previous years, and/or maybe there is a small print somewhere making an exception in the case that too many employees decide to donate.)
Recently, multiple suspicious user accounts were created on Less Wrong. These accounts don't post any content in the forum. Instead, they are used only to send private messages to the existing users.
Many users have received a copy of the same message, but different variants exist, too. Here are the examples I know about. If you have received a different variant, please post it in a comment below this article:
I don't know yet about anyone who replied and got scammed, so this is all based on indirect evidence. If you got scammed, please tell me. If you are ashamed, I can publish your story anonymously. Your story could help other potential victims.
Most likely, the scheme is the following:
(Thanks to ChristianKl for explaining the system in the Open Thread.)
If you replied to the original message and now you are already in the middle of the process, please inform your bank as soon as possible! Even if the step 2 didn't happen yet, so you can still get out without losing money, warning your bank about the scammer could help other potential victims.
Warning: If you have already received a check or a payment confirmation, and someone is asking you to send the overpayment back quickly, do not send anything. The check or the payment confirmation is fake, and the goal is to make you send money before you find out. (Thanks to qsz for explaining.)