Sometimes its cheaper just to pay the taxes.
Shell has done the cba and found it is cheaper to pay the Gov't for their use of heavy lift aircraft and support than investing into a standby safety infrastructure that they would have to use.
Just like in the Gulf with BP, they didn't have a safety infrastructure available and had to use Gov't and outside help.
Both companies have determined that the Gov't will bail them out if a emergency happens.
Bingo. These companies have more in common with welfare cheats than Adam Smith.