Warning instead of blocking marked timespan

Is there a marked timespan type similar to dhx_time_block, which allows an event to be planned on a maked timespan and dispatch an onLimitViolation on conflict?
In our planner we are displaing absence as marked timespan. Since there is different reasons for absence, we will allow the planner to plan an event, even on marked cells. In stead of blocking we will display an warning.

Looks as there is some functionallity for this

    type: "absence"

  scheduler.attachEvent("onEventChanged", function (id, ev) {
            var isAbsence = scheduler.checkInMarkedTimespan(scheduler.getEvent(id), "absence")
            if (isAbsence)
            alert("Display waring");