Kappa Kappa Psi does not support or encourage the display and/or use of any regalia/paraphernalia (Cofa, Letters, fraternal calls, handshake, etc.) or any other aspects of the Fraternity by anyone other than duly initiated Brothers of the Psi (and honoraries, when such is the case). Until one has has earned the right to wear these items, they are not to be worn.
Besides, we have symbols/regalia specifically for MIKKYs (or MIPs, or "pledges", depending on your point of view)...

These symbols are as visible as the Fraternity letters. For those who think letters are necessary to identify/publicize the journey of prospective (read, not "new") members, these symbols leave no doubt for anyone who witnesses them.
I also understand the reasoning behind the position of many of the Greeks on GC. Membership is
earned, it is not given freely. And when you start a MIP, you have earned only the privilege to participate in that MIP. It isn't a free ride (or at least, shouldn't be) and it's definitely no sure thing that you will cross. Many MIPs will start, but fewer will finish.
In short: Until you complete the journey to Psi, you should not (and will not) wear the letters. It's as simple as that.
Period.
There is an obvious difference in "culture" between two principal (and opposing) viewpoints where each side has presented reasonable arguments for their position. While I do respect the opinions of the opposing side, this is a situation where the two schools of thought will simply have to "agree to disagree".