On a totally unrelated issue, but yet noted in a recent response... If the catcher went to the mound without requesting time, I wouldn't call time for him. I might ask him while he's on his way if he's forgetting anything (so only he and I can hear it). But why should I "assist" the defense in making a "time" call that could benefit the offense? Catchers know to call time... They know if they don't hear time, then they need to ask again... If they don't, well it's not my job to train them. Last time they do it I bet too! Not that you want to throw the guy protecting you under the base, but if a defensive coach asks I'd have to say because he didn't call time...
At the levels I do, you just do it. You'll look like a redass looking for trouble if you don't. It's part of the accepted social graces. If the manager wants a trip or the catcher wants to talk to his pitcher, you call time as soon as you recognize the situation, unless there is still unrelaxed action. Often they'll ask, but you still give it to them if they don't. I would say that it may be a good idea to do this at HS and below. It'll avoid you having to clean up messes.