Ninja looting expired SAPs is a valid reason for solo players to go to PvP islands and if you remove that, you will remove yet another potential PvP target. Its the only reason a PvE combat guy would ever go to beta; this guy might be more likely to try his hand at roams and small scale PVP in the future.
Its not hurting you guys that some solo player took the risk to snatch a rotting loot can, but didnt want to attack it (even if he could). Do you think it would incentivise someone to get a group together to actually attack a SAP? Cause if they were gonna put in that effort, they would hopefully try to roam an island instead.
Leave it as is and if its a big concern, get your loot off the field when the SAP is done (the power to resolve this issue is already in the hands of the terminal owners).