'Rest Interruption' encounters are (or should be) always balanced around being a fair to moderate challenge, but not a dangerous or lethal one, to a party that is tapped out of expendable resources. Furthermore, they're designed with the knowledge that the party can feel free to use up all of their remaining resources with impunity on that encounter, because they will definitely get a full refresh after it. The reality is that when they are designed in this way (as most video games that have implemented rest interruption encounters have done), it doesn't end up encouraging people to hold back 'just in case' resources, or to rest after every fight at all - neither effect actually tends to end up ocurring, at least not beause of random encounter threats. If Larian does decide to implement an encounter system that can interrupt your rest attempts, or your evening camps, then I would like to have faith that they would also generally adopt this fairly standard principle for their design of them.