Question about a power of attorney document.

I'm fairly new and still getting the hang of this. A customer asked me to notarize a power of attorney document and on the document it take effect April 29th, yesterday. They haven't asked me to notarize with a different date which I would refuse if they did, but I'm questioning notarizing something on the 30th that on paper was supposed to take effect on the 29th. Has anyone run into this problem?