The answers to the clues below will have something in common. Can you determine what it is?

1. Customs document

2. Hilton's guest of a guest

3. Tendency to focus exclusively on a single or limited goal or point of view 

HINT:

Puzzle title: ELVIS SIGHTINGS

Answers:

 

1. Travel visa - travEL VISa

2. Hotel visitor - hotEL VISitor

3. Tunnel vision - tunnEL VISion

Credit: Harvey Estes