(CNN)Survivors of a school shooting in Parkland, Florida, returned from spring break Monday to new security measures that some students said made them feel like they were in prison.
How Parkland students feel about their new mandatory clear backpacks
Marjory Stoneman Douglas students encountered security barriers and bag check lines as they entered campus Monday morning.
Inside the school, administrators handed out the students' newest mandatory accessories: a see-through backpack much like the ones required at some stadiums and arenas, and an identification badge they must wear at all times.
The bags were yet another stark reminder of how much had changed since a former student stormed the hallways on February 14, gunning down 17 people, junior Kai Koerber said.
First, students lost their classmates and teachers. Now, with the bags, they're sacrificing their privacy for what he and others consider an ineffective security measure.
"It's difficult, we all now have to learn how to deal with not only the loss of our friends, but now our right to privacy. My school was a place where everyone felt comfortable, it was a home away from home, and now that home has been destroyed," he said.
The shooting galvanized a student-led movement calling for stricter gun laws, and some students used the clear bags to make a political statement.
Koerber and others attached an orange price tag to their bags. The $1.05 tag is intended to protest politicians, including Florida Sen. Marco Rubio, who accept money from the National Rifle Association, by putting a price on each student.
"We are doing this in order to demonstrate the fact that we stand together on all issues, and that we, as a student body, refuse to be reduced to nothing more than dollars and cents," Koerber said.
Senior Delaney Tarr tagged Rubio in a tweet of a picture of her bag with feminine products and the orange price tag attached to it.
"Starting off the last quarter of senior year right, with a good ol' violation of privacy!" she said in another tweet.
In addition to displaying the orange tag, senior Carmen Lo stuffed a sign into her backpack that read "this backpack is probably worth more than my life."
She also wonders how students will carry sports equipment, instruments and laptops.
"Many students are actually unhappy with the clear backpacks, as they believe that it infringes on their privacy, so they wrote messages on pieces of paper and put it into the clear backpacks," she said.
"We come to school to learn, so I don't think that we should need to subject ourselves to these measures. We shouldn't need to worry about our safety and our security while we are at school."
Koerber thinks metal detectors would be more effective than clear backpacks.
"Just implement a system that works. Similar to what they do at court houses and the airport!" he said. "It's terrible that girls will have no privacy concealing their feminine products, and these bags won't last a week with real textbooks in them. Metal detectors are a better solution."
The school district said it's considering whether to install metal detectors at the school's entrances. A letter from Principal Ty Thompson sent to families on Friday said that step has not been taken yet.
Clear backpacks may deter some from bringing weapons into school, but without metal detectors people can still conceal them in folders or in between papers, junior Isabella Pfeiffer said.
And backpacks won't prevent firearms from getting in the hands of dangerous people in the first place, she said. It would not have prevented the February 14 rampage, because the gunman was not a student.
"This isn't a solution to making sure that a tragedy like the one that happened at Douglas doesn't happen again," she said. "Many of us think that this is a way that legislators can pacify us instead of enacting actual change."
Junior Connor Dietrich used tissue paper to obscure the contents of his bag. He, too, thinks the bags are not the answer to preventing guns from getting into the hands of the wrong people, which is what he and other students are fighting for.
"You know it's only difficult because if we were being listened to and common sense gun legislation was brought into play we wouldn't need all of this to be safe."
Junior Jack Macleod said he is not opposed to the clear backpacks if they are used with other safety measures, such as metal detectors or wands.
But safety may come at the cost of a productive school environment, he said.
"I definitely feel safer, but in no way is school going to be a place of cognitive education and creativity when it feels like a jail cell," he said.