It is very honest of Fordman to say that; and I admire his honesty.
As I have never seen "Surprise Inspection", and it is not listed on this site; I am unable to comment on how I feel for I don't know what has been written.
In general, I know that 'copying is the greatest form of flattery' but plagiarism is a breach of copywrite; as all stories on this site are protected by copywrite.
Is taking inspiration the same as plagiarism ? That depends. If you wrote about garbage trucks, it is not, because @ 75% of trashcan stories have one. However, if you read a story where the hero escapes compaction by turning the garbage truck over on its roof; then it might be a bit much to write your own story and use the same means of escape, because that is clearly copying someone else's idea. Rest assured the amount of copying involved in the complaint of mine, is not just the same ending, it was the whole theme of the story, which was copied, just with some minor tweaks.
As for Steve's point about name changes and other sites: Maybe I am incorrect, but I think Gromet is able to see whether two or more names have the same IP address. This could highlight someone re-joining under another name. As for other sites, we can only really monitor this one. It is up to the other site(s) to have their own monitors. But there is no reason why we cannot bring a problem to their attention if they had not spotted it - just like you did Steve.
When in doubt, Fordman, I think Gromet's suggestion in the Writer's Guide is a good yardstick - if in doubt contact the original author who inspired you and have a chat before committing fingers to the keyboard. If the original author is happy, no harm done. If the original author is unhappy, problem averted. The original author might not like you copying xyz, but have no problem with you copying abc. It is about communication. I think a large part of the problem is that people do it sneakily, and then it looks underhand, even if it was not intended as such.
Indeed, authors can even collaborate and bounce ideas of each other. I have some written stories this way.
Better to make a friend than an enemy.
I hope that helps.
Daffy