Darn good guess, that's exactly what is going on, though by a somewhat circuitous route. Thank you!
25 years experience programming. Millions of lines of code. The guess was that you recently modified the forum source code for the showcase i.e. there was no sandbox extant. From there it was pretty safe to assume that you had to mess with permission checks to make a sandbox for certain users. Probably had to add a new category of permission SHOWCASE. Easy to accidently skip past some other permission checks once you identified a SHOWCASE authorized poster posting to the showcase forum.
I need development help, by the way, if you're familiar with web programming or interested in learning.
Almost all my work has been in various assembly languages (mostly 80x86), C, and Visual C++. I'm expert with lower level TCP/IP protocols, Winsock, peer2peer and client/server applications but have done little at HTML level inside a browser - just a few things on as needed basis mostly to embed banner advertising with ad agencies like Double Click in stand-alone applications where there's no browser to fetch and display the GIF adverts from their server. Email me with a quick description of your programming environment and I'll see if it's up my alley or if not whether it looks interesting enough to spend some time learning. So far I've mostly avoided mucking around in the script code for WordPress on Uncommon Descent. Micah Sparacio does the harder technical stuff and I have all the fun.
Never paid any attention to that side of the discussion. The parts that got my attention were related to the Forum Guidelines, mostly rule 10. For example, I didn't feel comfortable with portions like, "You're a liability to anyone who associates themselves with you because of your stinking rotten personality." We try to keep discussion focused on the topic and not the people.
May I plead
nolo contendere and throw myself upon the mercy of the court?

It's actually better if I don't interact with John. Restraint isn't one of my virtues and John could drive a saint to drink.
Edited by DaveScot, : Added final paragraph.