Or mistakenly, especially with the incentive of a reciprocal endorsement for a skill they have (or don't). I send you a C# application, how do you know I wrote it, I send you the code , how do know it goes with the app, that I wrote, it, which bit I wrote, that all the mistakes in it were not down to me, or to be fixed in the next version. How capabale a judge are you of good code. Even if you are how does it match up to the spec?

Duff endorsements can happen, so will happen, then all endorsements will be seen as having the same value, i.e. none whatsoever.

Anyone who takes endorsements done via this mechanism derserves the collection of liars, sychophants and planks they are going to get.
They have about as much value as a photoshopped 1998 MCSE, handed out by the non-existent university of X.