Visible crew/equipment: At the very beginning of the episode where the RV crashes against a rock in the middle of the desert, a camera badly hidden behind a bush can be seen on the right side of the screen immediately after the crash. (00:00:57)
Visible crew/equipment: When Walter talks with Jesse outside the Mesa Credit Union, just after giving him the money to buy the RV, a boom mic pole can be seen reflected on Jesse's car door. (00:36:12)
Visible crew/equipment: When Walter puts the mask over Jesse's unconscious face after drugging Emilio and Krazy-8, in the POV shot of Jesse where the camera is looking up at Walter, the reflection of the camera can be seen in Walter's mask. (00:51:05)
Visible crew/equipment: At the very end of the episode, right after he tells Jesse how he used the red phosphorus to kill the gunmen, Walt leans down to vomit. You can see his microphone transmitter under his shirt. (00:54:20)
Visible crew/equipment: Just as Walt is saying the line about checking to see if the other one is dead in the RV, the edge of the set comes into view very briefly on the right hand side. (00:15:10)
...and the Bag's in the River - S1-E3
Visible crew/equipment: At the start when Jesse looks over his shoulder at Walt, a stage light and what appears to be a light screen are reflected in his mask. (00:02:00)
Cancer Man - S1-E4
Visible crew/equipment: When we see a close up of Jesse stamping on the spliff you can see an orange marker on the floor where Jake is stood. (00:42:20)
A No-Rough-Stuff Type Deal - S1-E7
Visible crew/equipment: When Tuco is beating the other thug to death, the camera pans first on Walter, then Jesse. When it is on Jesse, the entire crew can be seen in the reflection of his sunglasses. (00:45:35)
Visible crew/equipment: When Tuco shouts "Yeah look at this" the camera cuts to Jesse and in his sunglasses you can see a crew member reflected. (00:03:40)
Visible crew/equipment: As Walt and Jessie get into the car at the start a light screen is reflected in Jesse's glasses. (00:04:20)
Visible crew/equipment: When Jesse gets into his car the second time, a boom mic is reflected in his door. (00:09:40)
Visible crew/equipment: When Skyler is rubbing oil on her stomach and preparing herself in the bathroom, a camera and cameraman's hand is visible for about a second from the left side of the mirror. (00:10:30)
Visible crew/equipment: Just as Hank gets given his present at the office, several T marks are visible on the floor. (00:39:10)
Visible crew/equipment: When explaining to Hank and Jr what the doctor thinks caused his memory loss, a light screen is reflected in his glasses. (00:40:30)
Negro Y Azul - S2-E7
Visible crew/equipment: When we are shown the blue truck at the gas station, there is an entire film crew reflected in the chrome bumper. (00:18:15)
4 Days Out - S2-E9
Visible crew/equipment: When Walt tells Jesse that the 19lbs of Meth works out at $672k each, a light screen is reflected in the very corner of Walt's glasses. (00:17:30)
4 Days Out - S2-E9
Visible crew/equipment: Walt and Jesse get stranded out in the desert. We see Walt cough up some blood and Jesse stand behind him. In this shot you can see the reflection of someone move in Walt's glasses, despite them being alone and still. (00:32:30)
Chosen answer: It is part of the ritual for la Santa Muerte. It is a sign of humility and sacrifice.
djm