They will just think that you are maining them and keep veilers, tt, book etc in.
When it comes to Card Car D (I know I'm a bit late on this but I'm going for it) I cant help but think it might not be all that solid in main deck. One of the things that is the most damaging about Chain Burn is that game one it leaves your opponent with dead cards, like Warning, Veiler, and Torrential. While obviously they can play those cards but good luck finding a way for them to not neg themselves when they activate it. Needless to say, those cards get sided out game 2 and 3 for your opponent, so I'd much rather side in Card Car D after all the answers to it have been sided out, then potentially side them back out game 3 just to keep them off balance.
This deck really comes down to it's ability to side and it's ability to keep your opponent's momentum broken and keep them off balance, and siding into and out of Card Car D as opposed to maining them does that better in my honest opinion.
I think people should see ccd as a risk vs reward kinda like pot odds in poker.
If you assume your opponent is running 40 cards and 5 outs to ccd on average (not counting warning/solemn) the probability of your opponent having one or more outs is 57,7% on their turn 1, 63,9% turn 2, 69,3% turn 3, 40,4% turn 4 etc. 1/2 veilers out of 2 when you go first = 23,7% and
1/2/3 veilers out of 3 when you go first = 33,8%
For the full picture you would obviously have to calculate the odds of drawing cardcar D, add in jar/pod/reckless/accumulate, the probability of them already having used one of these outs, the disadvantage of having 1 les card vs. the advantage of having 1 more, taking your meta and bad/good matchups into account as well as the disadvantage of not being able to set the cards/summon lava golem etc. etc. (I don't got the time right now xD). My point is instead of just going with what you feel is best it is actually pretty easy to make an educated decision on whether or not to run ccd.