A predator sees creature A and creature B. He notices the similarity of creature A to creature C, which he knows will make him sick, so he eats creature B instead. Creature A has survived because he resembles creature C.
You suppose creature C to be poisonous or unpalatable. You should prove it first.
I clearly stated in point 4: the predator knows, by instinct or experience, that eating creature C will make him sick. Isn't that proof? Try again.
There is no better evidence than contents of stomach of free living birds. But such information do not prove darwinian claim that birds avoid eating "unpalatable" aposematics (wasps, ladybirds).
If you find an "unpalatable" aposematic (or a mimic) in a birds stomach, you have found proof that aposematism (or mimicry) does not provide immunity to predators. But, as was said over and over again, this is not what darwinists claim.
No matter how many birds stomach contents you study, you will never find the remains of all the creatures the bird didn't eat. And the bird didn't eat these creatures because:
a. He didn't spot them because they looked like a leaf or a twig or some bird poo;
b. He decided not to eat them because he remembered eating one before and it made him sick;
c. He mistakenly identified them as a creature that he remembered eating before and it made him sick.