Simon,
While plenty of folks don't adhere to it, I think the project standard terminology deems boinc.exe (and substitutes for it) to be the client, while each executable which actually does project-specific computation is called a science application, or science ap for short.
As there have in the past been after-market substitutes for both categories, no few end users have actually gotten confused as to which was meant.
While I don't think this point is worth any retroactive cleanup campaign, I suggest that for tidiness sake you avoid referring to science applications as clients in the future.
I'm not saying this out of dis-respect or malice. On the contrary I'm quite grateful for the effort you have expended, the results you have obtained and shared, and the careful documentation you have provided. You've made it clear you wish to hear of programming bugs, so I'm submitting this as a documentation or posting bug report.