No. Vorführeffekt is used for anything that suddenly behaves differently when an audience is present. Be that features that suddenly don't work when observed, or bugs that suddenly don't reproduce anymore, etc.
I think I get what you're trying to say, but by definition an observation requires an audience, even if it's an audience of 1. Maybe say an increased audience size?
The translation is wrong because it makes things unnecessarily complicated. The term Vorführeffekt is used when something suddenly behaves differently in a not desired way when shown to others. The argument about double negation is logically right, yet entirely theoretical, as no sane person would ever describe or translate the effect in such a doubly-negated way to someone else.
