Two scofflaws have been charged with trespassing at Yellowstone National Park after walking to the Old Faithful geyser for a closer look and cellphone photos last week.

The two men — who have yet to be identified by park officials — were photographed standing next to the geyser and looking down into the steam-filled hole by other visitors. Park rangers were notified and the two visitors were ticketed and were given a chance to come back to the park — this time to appear before a federal magistrate at Mammoth Hot Springs in December. Violation notices for mandatory court appearances have been issued to both men, park officials said.

This is not the first time visitors have been charged for trespassing around Old Faithful. Last September, Gabriel Villalva of Colorado was charged with foot travel in a thermal area, interference with a government employee, resisting a government employee and disorderly conduct. Some visitors thought his goal was to urinate on the site.

Villalva pleaded guilty to the misdemeanor counts of foot travel in a thermal area and disorderly conduct last November, with the other charges dismissed by the U.S. Attorney’s Office. He was ordered to pay $50 and received a sentence of five years of unsupervised probation, during which time he must obey the law and stay out of Yellowstone and Grand Teton national parks.

Villalva’s sentence for his transgressions in Yellowstone may have been lighter because he was facing more serious charges in Cheyenne; Laramie County authorities alleged that, just days after trespassing at Old Faithful, Villalva led Cheyenne police on a chase.

Trespassing can also have deadly consequences: In Yellowstone’s history, more than 20 visitors have died after being scalded by boiling waters.

The last person to die in a geothermal accident was Colin Nathaniel Scott, 23, of Portland, Oregon, who died in a hot spring near Porkchop Geyser in June 2016. Scott and his sister illegally left the boardwalk and walked more than 200 yards in the Norris Geyser Basin.

Thermal area safety is an extremely important part of any trip to Yellowstone, said park spokesperson Rebecca Roland.

“We ask visitors to take the Yellowstone Pledge before coming to the park and to read the park Visitor Guide for safety, rules and regulations,” she said.

According to the park, deep circulating water in the Old Faithful system can exceed the boiling point of water.