In its report, the tribunal said Parker's criminal behaviour would have come to light earlier had Mr Hovell taken all steps to ensure pupils' safety when he found out from police about the overnight stays.
The chief executive of Te Runanga o Ngati Kahu, Anahera Herbert-Graves, said some members of the community and some teachers did raise concerns about Parker's behaviour with Mr Hovell, but no action was taken.
"They should feel validated that Stephen has had to pay a price."
Principal's Federation president Phil Harding said there needed to be clearer processes on what principals and teachers should do if there was an allegation of illegal behaviour of a colleague.
"We need to work with the police and with other helping agencies to build a set of protocols and expectations for school leaders to follow when such tragic behaviour threatens to overwhelm a community."
Teachers Council spokeswoman MaryRose (crct) Painter said there had recently been a big push to make sure school principals were aware of the requirement to report behaviour or teaching that is not up to standard.
"There are clear thresholds where principals must report to us, they don't have a choice, they need to do it."
The tribunal's decision sent a message to principals, she said.
"It is certainly reinforcing that principals and professional leaders have a responsibility to keep children safe ... and to make sure they know what their staff are up to."
Ministry of Education head of sector enablement and support to Katrina Casey said they would be drawing schools' attention to the decision.
"And reminding them again of their obligations in dealing with sexual misconduct allegations, and of the support that is available to them in doing so."
New Zealand School Trustees Association president Lorraine Kerr said they were looking at the "big picture" in terms of the report's implications.
Processes needed to be put in place for when that type of offending happened again, Ms Kerr said.
"Because we all agree that it's not an if, it's a when."
Mr Hovell's lawyer Bryce Quarrie said his client would have no comment about the decision.
School board spokesman Stephen Allan was unavailable for comment.