Then there are the folks who are smart enough to know which rabbi to ask which questions in the first place. They know Rabbis A, B and C don’t allow what they want to do. But Rabbi D is known to allow it. So after they did their rabbinical research they first ask Rabbi D. When the next question comes up that their research told them Rabbi D doesn’t allow, they find out that Rabbi X allows it. So, obviously, Rabbi X is their first phone call for that question.
This way no one could ever accuse them of Heter-Shopping, since they never asked a second rabbi for a different answer after not liking what the first one pakened.
That’s why it’s good to have friends to ask which rabbi to call for what questions.
Of course there are some rabbis who just let about anything. They can be relied upon for any question.