Protesters outside a west Phoenix Motel 6 on Friday called for a boycott of the motel chain and the firing of employees who gave guest lists to ICE.

Motel 6 admits at least two of its Phoenix motels handed over guest lists to U.S. Immigration and Customs Enforcement. ICE then arrested a reported 20 undocumented immigrants at the motels.

Some have raised questions about the legality of the operation.

Can motels turn over your guest information to law enforcement, and what can law enforcement do with that information?

"I was surprised," Arizona State University law professor Angela Banks said about Motel 6's decision to hand over the lists.

But Banks said it's not illegal if the motel volunteered the information.

"They were not compelled by the government to provide that information," she said. "They simply voluntarily provided that information."

The U.S. Supreme Court ruled two years ago that police can't force motels or hotels to turn over guest registries.

"If ICE had come to Motel 6 and said, 'Please give us the guest list,' Motel 6 would not have had to do that, absent a (search) warrant," Banks said.

The next question: What did ICE do with the lists? Were some guests racially profiled or was every guest run through an immigration database?

"Are all the names being run or just the Latino names?" Banks asked. "Until you have that information about what was happening, you wouldn't be able to draw that conclusion."

You don't have to have done something wrong to be troubled by the idea of motels or hotels handing over your information to police.

Banks says that if you're concerned, ask a hotel manager what they do with the information gathered on guests.