I don't see how that's an apt comparison. By taking a job you aren't agreeing to never go for another job. If you leave the job you are expected to give proper notice, that's it.
A more apt comparison would be a marriage proposal. You aren't supposed to accept the proposal then play the field while deciding if this is really what you want to do.
Folks aren't questioning going through the recruiting process, he should do what he feels he needs to do. But what he's doing isn't showing commitment, it's showing that he likes us and wants a spot held. Maybe he ends-up a husker but we certainly have to keep recruiting said spot.