As far as I'm concerned (and, I could be way wrong) OLCCs don't mean jack squat unless you're in a GFT session. (which, I never have been)
Well... OLCC's aren't just a slap on your wrist.
If you are not a "repeat offender", they do just amount to a documented slap on the wrist.
The reason Express does the OLCC "thing" is that it allows them to possess documentation that a particular employee did indeed commit a "transgression" - for which they have chosen not to "offer" a Warning Letter. Many times, the evidence for the transgression is so slim, that if they tried to offer a Warning letter and the employee GFT-ed it, management would lose.
However, by compiling OLCC's, Express is able to use "prior history" as a justification for issuing a Warning letter if something does come up in the future. If an employee does transgress in a manner that they have been previously issued an OLCC for, they will receive a Warning letter for that. Express will compile OLCCs on troublesome employees solely to give them the ammunition to start kicking out Warning letters should they so choose. This is their legal cover for getting rid of employees which they no longer want. Have a union agitator in the station, start issuing OLCCs for trivial issues and even trumped up issues - to either intimidate or build documentation to support Warning letters in the future. I was there, experienced it.
As you well know, the things which OLCCs can be issued for are for whatever management decides they want to spend the time entering the data into your personnel file. If an employee isn't causing management trouble, they tend to ignore minor issues that come up (the "nasty gram" in your mail box). If they are gunning to either scare you or outright get rid of you, then every little thing that you do (or they can trump up) will result in an OLCC - which they can then use against you at a future date to issue a warning letter.
I've also know that of late, Warning letters are being issued with built in "probation clauses" - if you get a Warning Letter for issue X, any recurrence of issue X in a 90 day period following the issuance date of the Warning Letter will constitute grounds for termination. So the old "three strikes and you're out" (Three active warning letters to terminate), seems to be more or less redundant, and it is now "one strike and another within 90 days - and you're out".
Don't take OLCC's lightly. You can't refuse or contest them, they stay in your record permanently and they can be used to justify issuance of Warning letters should management so desire. OLCCs are management's secret weapon to give them and FedEx legal cover to eventually dump you should they desire.