Firstly, people would definitely abuse 'avatar-like attacking' in the same way that they abuse avatars (look in korroloka tunnel to see what I mean).

Secondly, if you can't handle getting agro without your trusts engaging immediately, you need to use the same methods to avoid detection that we always had to before trusts... Sneak/Invisible, and don't AFK where mobs spawn/wander.

Thirdly, and in response to your second post: Healing waltz will cure silence, not just silena; but if you aren't playing as /mage or /dnc, then use the WHM Trusts depending on the situation. Cherukiki (the one that you mentioned) will stay stationary when you engage a monster, until you are out of range of her, so you can just move from her. Easy. Ferrous Coffin and Kupipi, however, will melee so they're not a good option when fighting mobs that can silence them.