Travel snafus are frustrating. In the heat of the moment, it’s easy to see the customer service agent telling you your flight is delayed or canceled as a personification of the airline — and therefore responsible for your inconvenience.

A new survey by the Government Accountability Office shows that passengers regularly take out their frustration on airlines’ ground employees. The GAO queried 104 gate agents in March and April, and 96 of the respondents said they had been verbally harassed on the job. Twelve said they had been physically assaulted by irate passengers.

But, the GAO admitted, its survey is hardly scientific.

“No comprehensive data are available to determine the nature and frequency of passenger assaults — e.g., verbal threats, attempted physical acts, or actual physical acts — against airline customer service agents at airports. This lack of data is due, in part, to the limited federal role in addressing such assaults,” the agency said in its findings.

Related: 9 ways not to be an annoying airline passenger

Many gate agents are members of the Communications Workers of America (CWA) union, which praised the report in a statement to TPG.

“We’re glad to see the GAO report reinforce what we’ve been saying — that the assault of passenger service agents by passengers is a serious problem,” the union said. “The report shows that more needs to be done to enforce existing laws to protect passenger service agents, including provisions on passenger assault that CWA members fought to get included in the FAA bill passed last year.”

While law enforcement officers and other stakeholders generally think existing procedures are sufficient to address airline ground staff abuse, a new federal law requires airlines to develop employee assault prevention and response plans, according to the GAO.

Frustrated passengers should remember that common courtesy goes a long way toward making travel mishaps easier for everyone. Equally important: remember the gate agents who tell you your flight is delayed have little control over the issue.

This story was originally published on The Points Guy. Sign up for the TPG daily newsletter and wake up to unbeatable flight deals, travel industry news, and credit card bonuses that let you travel first-class to some of the world’s most incredible destinations at a fraction of the price.