According to the official New Jersey COVID-19 Information Hub as of March 8, 2021 (emphasis in original),
Travelers and residents returning from any U.S. state or territory beyond the immediate region (New York, Connecticut, Pennsylvania, and Delaware) should self-quarantine at their home, hotel, or other temporary lodging following recommendations from the CDC:...
The self-quarantine is voluntary, but compliance is expected.
The site comes out and seems to say that the quarantine is voluntary, but then says that "compliance is expected".
Is there a legal penalty or intervention for not following the above guidelines, or are these rules enforced solely through social pressure (frowns, social ostracism, gossip, etc.)?
To be clear, I'm not asking for the socially responsible or healthy choice, but the legal one. For example, if someone were to walk into a NJ government office and loudly proclaim that they had just arrived from Texas and won't be self-quarantining, is there anything they can do except appeal to the person's conscience? In other words, is the description of the quarantine as "voluntary" more a recognition that public health authorities are not actively monitoring and pursuing visitors as a matter of practice or is it a recognition that the state literally has no legal means to force visitors to comply?
Also to be clear, I'm asking solely about the general quarantine described above. Cases where someone has tested positive for COVID-19 or been specifically identified as a close contact of someone who did are out of scope for this question.
Why someone would want to travel to New Jersey is out of scope for this question.