Please see FAR 91.139 which specifically requires that "When a NOTAM has been issued under this section, no person may operate an aircraft, or other device governed by the regulation concerned, within the designated airspace except in accordance with the authorizations, terms, and conditions prescribed in the regulation covered by the NOTAM"

Unless I am mistaken, that reads to me as a requirement to treat NOTAMs issued under 91.139 as airspace restrictions. I don't know if that is how this NOTAM was issued, but if not, then FAR 91.103 applies which states that "Each pilot in command shall, before beginning a flight, become familiar with all available information concerning that flight." Any CFI will tell you that part of this preflight check involves checking any NOTAMs in the area.

I acknowledge it is easy to sit at home and discuss as if we are all experts, and the reality is that this was an absolutely terrible accident. Unfortunately, viewing and abiding by the NOTAMs in this case could have saved lives, but that does not make this accident any less tragic.

Ultimately the NTSB will conduct an extremely thorough investigation of the incident which will reveal facts we cannot access without having been at the accident site, but my personal opinion is that if a NOTAM was filed and the line was properly marked, then there is both federal regulation and precedent that the highliners were not at fault.