My own operating procedure is to add a SLOP if I'm doing IFBPs. Especially in Africa and especially during the Haj! It's free, easy and improves the safety margin by a huge factor. No one has to do it, unless it's in their SOPs (I'm aware of at least one company who has included it). It's an airmanship call and personal preference.
And with everyone maintaining the airway centreline within their own wingspan thes days, it makes a lot of sense.