Not to be pedantic (ok a little bit), but you don't normally include any costs on your balance sheet, but you might want to include them on your income statement.
So do it? I really don't see the problem. I get that Deliveroo puts you on their platform even if you don't agree (the apps where I live don't do this), but if that's the case the restaurant is still getting the full price for selling their food. The customer pays the extra 20%.
No it doesn't make them fascist, and that's not what Eco is saying. Combining Saint Augustine and Stonehenge is syncretism, which is a symptom of Ur Fascism (as discussed) above. Symptom does not equal implication.
I am not sure I understand your use of the word "symptom". Being syncretistic, by itself, is clearly not indicative of fascism (as you point out all religion is syncretistic to some extent, so is art, etc.), but if you see many of the symptoms that Eco describes - not just syncretism, but also traditionalism, irrationalism, uniformity of thought, fear of difference, populism, nationalism, etc. - then syncretism becomes part of your "fascism" diagnosis. By themselves these things can be part of various strands of political thought, only together are they Ur-Fascism.
Just like a headache, by itself is not indicative of a disease, but can be a clue in combination with other symptoms.
I returned to this essay when I saw the photo of the Jake Angeli in the Capitol - a Q-supporter wearing an Indian buffalo mask and a tattoo of Odin, storming the capitol alongside evangelical Christians. Relevant quote:
This new culture had to be syncretistic. Syncretism is not only, as the dictionary says, “the combination of different forms of belief or practice”; such a combination must tolerate contradictions. Each of the original messages contains a sliver of wisdom, and whenever they seem to say different or incompatible things it is only because all are alluding, allegorically, to the same primeval truth.
As a consequence, there can be no advancement of learning. Truth has been already spelled out once and for all, and we can only keep interpreting its obscure message.
[...]
If you browse in the shelves that, in American bookstores, are labeled as New Age, you can find there even Saint Augustine who, as far as I know, was not a fascist. But combining Saint Augustine and Stonehenge—that is a symptom of Ur-Fascism.
That's fine - that's awareness marketing and if you want to do it with online ads that's up to you. But then you should consider it compared to your other awareness marketing channel.
But the promise of performance marketing is exactly this immediate connection between ad spend and performance (i.e. sales).
What about the morality of the situation? From a purely self-interested perspective I think its pretty obvious there is limited benefit given the risk. But if you are relatively young and healthy, expecting others to get the vaccine so you can benefit seems immoral.