Some wear disguises. Others don't care if you see their face.
Many are armed with weapons. All of them want one thing - money.
For tellers, a bank robbery is frightening and dangerous.
Meredith was one of the more than a dozen tellers robbed by the infamous Geezer Bandit.
"He pulled out a gun," she remembers.
"I just wanted him to leave, I didn't want to know if the gun was loaded, I didn't want him to use the gun," Meredith said.
So, she gave the Geezer Bandit, all the money in her drawers.
But to her surprise, he didn't leave right away. Instead, he waited for her to get more money.
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“He said hurry up and go, and go get more, or I'll kill you," Meredith said.
Why would someone like the so-called Geezer Bandit be willing to wait longer, when there's a good chance someone in the bank may have hit the silent alarm.
"He knows what he's doing what he's doing, when it comes to robbing the banks and what's working for him," said Darrell Foxworth, San Diego FBI agent.
Foxworth said when a teller triggers a silent alarm, an alert goes to the bank's security company. That company will then contact local police. He says it usually takes less than a minute, depending on which bank.
"Certainly, there's going to be instances where certain banks, their delay may not be as prompt as other banks," Foxworth said.
Take for instance a robbery involving a bank in West Seattle. A teller hit the silent alarm notifying the alarm company, which is located 3,000 miles away in Cleveland, Ohio.
After calling the bank first to make sure it wasn't a false alarm, the alarm company worker then called police in Seattle.
According to FBI agents, it took about five minutes before officers were finally sent to the bank.
Instead of calling 911, which would alert Cleveland police, the alarm company worker called the Seattle Police non-emergency line.
“It's really unfortunate and that shouldn't happen,” said Rick Sanborn Seacoast Commerce Bank President in Chula Vista.
He says banks have to use alarm companies because local police don't have the resources to monitor silent alarms.
"You can get false alarms when someone hits the wrong button, and all of the sudden the alarm goes off, it's not really practical for the police to be the monitoring system for all the banks alarm systems," said Sanborn.
He says his bank uses an alarm company here in San Diego County and the company doesn't call the bank first, to make sure an actual robbery is in progress. The company immediately calls 911.
"What's important to us is safety, safety for our employees,” said Sanborn, “we want to have and every bank should have the highest and best systems available so that "A" you're employees stay safe and "B" you have very quick response times."
Safety and quick responses are big issues for tellers like Meredith,
Not only was she robbed by the Geezer Bandit, she was also a victim of the Ho Hum bandit, who has got away with at least 15 robberies.
In her opinion, bank robbers need to be caught as quickly as possible.
"Every time he robs a bank he hurts and affects the person that he robbed and possibly anyone else who was around at that time," she said.
FBI agents say whenever they notice a weakness in a bank's notification system, they address it with the bank's security director. Last year, there were 168 bank robberies in San Diego and Imperial counties. So far the FBI has been able to catch more than half the robbers.
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