I've worked in incident/crisis management for several big, complicated, grown-via-acquisition companies with a tangle of internal systems that were never quite fully integrated.
When TSHTF and we need some expertise from the original builders or operators of a system, it's a lot nicer to have them on another team than at another company. If they still work for us, somebody can make the case to them (or their boss) that borrowing them for a few hours to fix it is in everyone's interest. A lot of times they are in some kind of management position now and they kind of smile and say "Wow, I haven't thought about that system in a long time. Sure, I can take a look." and it's even kind of a fun diversion from whatever budget meeting they were in.
If they work for somebody else, the answer is often "sorry, I'm busy" or just a hangup when you explain who you are and why you are calling.
When TSHTF and we need some expertise from the original builders or operators of a system, it's a lot nicer to have them on another team than at another company. If they still work for us, somebody can make the case to them (or their boss) that borrowing them for a few hours to fix it is in everyone's interest. A lot of times they are in some kind of management position now and they kind of smile and say "Wow, I haven't thought about that system in a long time. Sure, I can take a look." and it's even kind of a fun diversion from whatever budget meeting they were in.
If they work for somebody else, the answer is often "sorry, I'm busy" or just a hangup when you explain who you are and why you are calling.