Click on the purple

We recently had a stack of legal papers to sign.  Each place where a signature was called for had a purple spot on the computer display.   We were asked to click the mouse on each purple spot and our “signature” would immediately replace the purple bit.  All our clicks were witnessed by two members of the staff but I want to avoid taking a test on what I “signed”.  We did discuss what the papers said a week or so beforehand but still…