I suppose so, yeah. It is to prevent the EAS (Electronic Article Surveilance) tower from being triggered.

Basically, all tags have an electric component inside them which gives off a magnetic field (well there are apparently different types of fields that are used in different versions but I think that’s the jist of it. ). The tower at the exit looks for any magnetic field and sounds an alarm if it is detected. The aluminium foil is used to block that field so that it doesn’t escape past the container.

Tags (including sticker tags) work by using a capacitor (which stores energy to give off charge/current when connected to a circuit) connected to a coil (which gives off a magnetic field).