You cannot trust them "absolutely". But again you cannot trust anything "absolutely". You have to "relatively" trust them. For myself I follow these guidelines:

1- Never scale up escrow trusted amounts: (If the community trusted this escrow with 100-200BTC in the past, Don't go ahead with 1000+BTC deals with this escrow -_-!)

2- Never do any transactions in private (Self explanatory)

3- Have everything cryptographically signed by a known key for the escrow (Self explanatory)

I hope this helps.