"You probably could if you had a school with 30 kids in it."
But expecting to keep tabs on every child once the final bell rang was not realistic for most urban schools, she said.
"If you have got 260 [children] being picked up by parents every day, [parents] flood in at 2.15pm and they flood out at 2.30pm.
But Mrs Walters said it was not always mothers picking up their kids. "Sometimes it's auntie, sometimes it's granddad."
"The only thing you can really do is be on guard for specific people if there is a known protection order."
Copies of all legal custody or protection orders were kept at the school so teachers were familiar with them, Mrs Walters said.
"We make a point that that person doesn't enter the school grounds."
But schools had to be "sensible" about the measures they took.
"If someone wants to get hold of a kid badly enough, they're going to get to them. "[Featherston school girl] Coral Burrows was abducted by someone she knew very well who would normally have picked her up and dropped her off without question."
In 2003, the 6-year-old youngster was murdered by her stepfather after Coral's school failed to alert her parents she hadn't arrived.
Coral had been reluctant to go to school so her stepfather, Steven Williams, who was high on methamphetamine, beat her to death and dumped her body.
Authorities were notified when Coral didn't return home from school at the end of the day. Her body was found 10 days later.
Ministry of Education spokeswoman Katrina Casey said responsibility for student safety rested largely with individual schools.
"Schools have responsibility for the health and safety of children while the children are at school. They generally have procedures in place to record custody arrangements for children and monitor these matters closely."
However, New Zealand Principals' Federation president Philip Harding said schools' responsibility for students' whereabouts was "vexed".
Last week's incident in Taupo was a case of a father taking his daughter from school, Mr Harding said, adding it appeared to have been an internal family problem that had led to that occurrence and the person was not a stranger.
"Generally, we've got this mounting sense of fear out there that's unfortunate and raising the anxiety of everybody when, in fact, these events are very, very rare," he said. APNZ