execLink() doesn't appear to really be a trusted function,
I tested it execLink() it is trusted.
or the requirement that a function that resides a library token needs to be non-player editable to be trusted has been silently lifted.
I wouldn't so much say the requirement has been silently lifted, more like it never existed
A macro is trusted if any of the following conditions are true.
1) It is executed from a lib:Token that is not owned by a player using [macro():].
2) The GM types something in.
3) Click on a macro that is non player editable.
4) I think (but I cant remember at the moment) click on a campaign macro.
Trusted macros can call non trusted macros and vice-versa, the trusted state will just flip between the two appropriately.
Then there is the "completely trusted" macros. If a macro is completely trusted and run by a player then it gets the special hilite (based on the options in the preferences).
For a macro to be fully trusted it must start from a trusted source (so a non player editable button), and only call trusted macros from that point onwards.