Metal slivers from improperly opened oil cans are regularly found in oil systems during strip-down and have some have been known to be the 'cause-for-removal'.
The was several incidents in the Australian Military where jet engines and turboshaft engines were removed for excess chips in oil filters. They were traced to chrome hardening off the screwdrivers used to puncture the can, not the can its self.
Synthetic oils are agitated prior to using to ensure the anti foaming agent is mixed.
Not having enough agent causes the oil to "froth", especially in gearboxes and transmissions, with the resultant fluctuations in oil pressure.
I find it intriguing that an argument is taking place because some believe that St Jack is doing "too much" - for f sake it takes less than a second to invert the can and shake it.
Cheers
BH