Why let me flag a post if you're not going to let me flag it?

Question

When you run out of flags for the day, the flag dialog still allows you to go through the process of flagging up until you actually click the button. You drill down through the menus, find the reason you want, and press the button only to see something like this:

Obviously, you get a little number at the bottom telling you how many flags you have, but the button is still enabled (implying that you can still flag):

At the very least, shouldn't the button be disabled even after you choose a flag reason if you're out of flags for the day?

However, what would be even better is if it were indicated on the post itself that you are out of flags via the disabling of the flag button in the way the edit button is disabled on per-site metas for users without full editing privileges:

Answer 1

Your suggestion is good, but there's alternative to this that's more in line with SE's design philosophy: leave the flag option enabled, but make it immediately display that red box.

I think there's a Coding Horror blog post espousing Stack Exchange's philosophy (I can't find it right now though), but you'll notice that they never disable options. You can click options to cast votes past your limit, and let you attempt to undo locked-in votes - it won't stop you or disable the option. But it'll let the action fail, then tell you why it failed. The idea is that the explanation of the failure at least tells you why you can't do it, whilst if an action's disabled and you have no idea why, that can be frustrating and confusing. The blog post explains it in more depth, and if anyone can find it, I'll be grateful.

That seems to be what they did here, except they need to put that failure at the beginning of the flag process, not the end.