Declared Var Dynamic Initialization = No Return Code Back?

[Adam Danischewski]

$>declare MYSTERY_CMD=$(which mystery) && echo "All set." || echo "Adding
to missing array ... "
All set.

$>MYSTERY2_CMD=$(which mystery2) && echo "All set." || echo "Adding to
missing array ... "
Adding to missing array ...

Declaring a variable doesn't seem risky enough to eat up the return code.
Is there a reason for this? I doubt that it would break anything to change.
It's a lot more intuitive and syntactically streamlined to check for
missing packages/software at the initial declaration as a sanity check.