The Marine Corps has a cutting score system that gauges whether an individual has satisfied the requirements for promotion. Each Marine competes with others in the same career field for the next pay grade. However, this system benefits some Military Occupational Specialties more than others.
The 'senior' lance corporal rank is an invention born out of necessity due to outrageously high cutting scores for the 03XX community. Most Marine infantry units are composed of Lance Corporals (E-3) and it's common to see Lance Corporals in billets above their pay grade because there's so much competition for promotion.
It's insulting to be tasked out on an E-3-and-below working party after doing a combat deployment. The unofficial 'senior' prefix was added to differentiate the war veteran from the idiot barely out of training. Here's why this 'rank,' unique to the infantry, is the best made-up rank.
1. They're getting out and everyone knows it
If you demand his respect without earning it, he'll tell you to climb up his ribbon stack and get it. He either has a job lined up or an acceptance letter to higher education. They're immune to the threat of an NJP because you can't stop time. Sooner or later, we all get a DD-214.
Ain't no boot no more.
2. They have the sharpest skates in the unit
The 'senior' Lance Corporal is the most cunning of all Marines. They know every hiding place and when to relocate. If they'd put half as much effort into doing work as they do avoiding it, they may have been promoted by now...
Regardless, having one in your entourage will guarantee you plausible deniability when sidestepping an incoming green weenie.
$20 says those unis are still crisp after a nap.
3. They have access to the "Lance Corporal Underground"
I can neither confirm nor deny the existence of the "Lance Corporal Underground." Allegedly, it's a large-yet-independent network of cells disseminating information throughout a unit.
Its accuracy of information is contingent on Marines who work in the S3 operations section or company office. Brass is known to supply counterintelligence because nothing should ever go according to plan.
Not. Even. Once.
Always a lie.
4. They will haze train Marines in the art of drinking
A 'senior' Lance Corporal is the last Marine to pass down the torch before being permanently assigned to 1st Civilian Division. He will teach junior Marines how to break each other out of prison team building exercises. The last chapter in anyone's career is bittersweet and the Senior Lance Corporal will always cherish the times he escaped justice memories forged with brothers-in-arms.
The days before barracks haircuts.