Can non-player entities activate triggers?

I decided to play around with the I/O system and discovered something strange:
Sentries, teleporters, stickies, etc can't seem to activate triggers.

Does anyone know if it is possible to get them to do this, and if so, how?

 

Triggers check what entities can trigger them through their flags; normally, only flag 1 (players) is checked. If you want to enable other entities to activate a trigger, check the box of the flag corresponding to that entity (or check flag 64 to allow all entities). You can also filter which entities can activate a given trigger by using filters. (Both of these pertain to multiple types of triggers, including trigger_multiple and trigger_hurt, among others)

 

Thank you! Argh, I managed to miss the one part of the VDW page that explains this!