@Sabertooth Good point! :)Scruples is more related to one's own conscience than to fear. If a client hasn't settled the matter with their own conscience, they have no business being in that chair.
At the same time, there is also something that is "plucking up courage", even as the person in question is already sure he or she wishes to be injected with the design. (So I guess that the word her would not really be 'scruples', right?)
There were some discussions on the theme of tattoo regret several months ago; but someone "plucking up courage" to receive an inking that he or she is sure about is less likely to be regretful later than is a person who gets inked in haste, on a whim, so to speak.