The one in whom he trusts is strong, not to be overcome in whatever he seeks or prevented by anything from fulfilling the request of one who trusts in him. If he is weak, however, one cannot have full trust in him even if it is established that he is compassionate and involved, for he will be prevented most times from carrying out his purpose. When these three qualities are united in him, trust in him is more fitting. pg 367
Daily Halacha
Many poskim hold that even l'chatchilah, one may recite Birkas ha-mazon anywhere in the room in which he ate, even if the room is so large that he cannot see the spot where he ate from where he presently is. The Halachah follows that view. Still, a minority opinion holds that whenever possible, one should bentsch in the exact place where he ate. This halacha applies to a meal eaten indoors. If, however, a meal is eaten outdoors, like at a picnic, Birkas ha-mazon must be recited at the exact spot where the meal was eaten or, when necessary, within four amos of the place.