Which, if your observation is true, that shopping cart return is motivated by utilitarian incentive. "If most of us do it, things work better and most us do so it makes sense."
Disagree with that all you like, you might well be right. I claim whatever it is it's a long way from promiscuity increasing with a decline in consequence for sexual activity from saying anything about the morals of those who would have loved to fornicate but lacked opportunity prior. Or indeed those so easily swayed by the "everyone does it" argument and were making a virtue of their lack off reasonable opportunity. Reasonable people may disagree with that of course.
Usually this kind of thing is imposed morality which isn't individual morals. "I want everyone else to follow what I think is moral by making (sex/drugs/other thing I dislike) have dire consequences through policy because I can't convince _them_ to do the right thing because _they_ lack [my] morals."