You are right, it is not allowed and is actually tax fraud. You should claim what you paid. If you paid by cheque, you'll have other proof if CRA requests it, but if you paid by cash it can be harder to prove, but not impossible. You could always report the caregiver to Canada Revene. I believe they have a confidential informant line, and if the caregiver has more children then just yours, they won't know who it came from.
A note to others looking into home daycares... An Individual care provider should be giving you their SIN as it is a requirement for filing your taxes. (See line 214 in the income tax guide)
http://www.cra-arc.gc.ca/tx/ndvdls/t...ymnts-eng.html If they do not want to give it to you, this could indicate that you may have future problems.