It's pretty safe to eat raw cake batter especially if the cake batter has no eggs.
Actually even with raw eggs in the cake batter you can safely eat the raw cake batter because as long as the eggs are pasteurized or contains no salmonella then you can safely consume raw eggs.
Although it's not recommended to eat raw cake batter or raw flour because of the potential of getting salmonella poisoning or at least getting sick from it.
I however have eaten raw cake batter for years and now I'm nearing 40 years old and have eaten cake batter since I was around 1 year old.
I have never gotten sick from eating raw cake batter and I still eat raw cake batter.
Sometimes I like to mix up a bowl of raw cake batter and just eat it like that from the bowl and it's delicious to me.
It's possible to get sick from it but very unlikely that you would get sick.