My reaction is as follows.
The purpose of a proposal of marriage (for that's what the comic contains) is twofold. Firstly it's for person A to make their feelings plain to person B, and this purpose, this purpose only, is well served by this comic.
The second, and more important, purpose is this: to invite the recipient of the proposal to respond. That response is crucial: The entire purpose of the exercise is tied up in the nature of the respose. It's absolutely, fundamentally, vital to the usefulness of that response that it conveys the wishes and intentions of the respondent faithfully and accurately. A response which is hasty, which is ill-considered, or worse, which is extorted from the recipient under artificial social pressure, is of no use whatsoever. In fact, to make a proposal in the way that this was made is to do exactly that -- it's extorting a reply under duress. As some comments to the comic said, "it's not like Wednesday is going to be able to say no", "no way the person's going to be able to say no gracefully", and so on. It's not acceptable to guilt someone into accepting a proposal of marriage, it's never acceptable to do so, and a confidence that she'll say yes, or an assertion from her after the fact, that it was okay, don't make it acceptable.
If someone does this to me as publicly as this, it'll be cast-iron evidence that they don't understand what makes me tick and a fatal breach of trust.
I've unscreened the comments in this post now. nwhyte came closest to working it out although he linked to another comic which isn't similar at all since the proposal itself took place in private. zarabee's views came closest to coinciding with my own.