People who have no money aren`t going to be blowing CERB on luxuries.
For people who do have money, CERB goes into the bank account and it is no different than any other money in there.
If someone pays rent, buys groceries, and hires a hooker, it doesn`t make sense to say the CERB money paid for the hooker and the other money paid for the essentials.
That being said, I do separate some cash at times, like when I receive a present and want to do something specifically with those funds.
My parents give me some cash for Christmas and I make a conscious effort to make sure I don`t hand those particular bills over to a stripper or masseuse.
I like to use those bills to buy some clothes and shoes, rather than just stick it in the bank with my other cash.