I guess this is similar to can you get someone too messy, to the point where you are messing mess not a person lol. However whilst testing my latest pie recipe I found one pie pretty much removed all facial features, eyes full nose just a slight bump and small mouth hole from breathing (pic on my profile for those interested)
Personally I love to see the person's reactions as they get messy, so tend to save face coverage for the end anyway, if someone is getting pied, I'd prefer non-obliteration pies at first, so we can still see the shape of their face and ongoing reactions. After a few pies in, then by all means, use something so thick it turns them into a messy blob.
I would say yes and to that, a pie can be so thick that it does not splat at all, For Example, I once used a toasted meringue pie from the store it was so thick I could not press it into my face at all. There was NO coverage on my face and it was a PAIN to clean up.