I'm sorry I can't answer your question on cages but pots in the ground might lead to rot of the bulbs due to drainage issues.

This is a response I wrote a few years ago to someone who was having problems with gophers eating lily bulbs (I have the same issues). It should work equally as well for voles (I have them too).

I plant all lily bulbs, dahlia tubers, and any expensive/rare/cherished plants in round cages made of chicken wire. I make taller cages for those plants that are prone to rabbit damage and leave about 18 inches above ground to protect the stems. I make the cages large enough to accommodate future root growth and multiplication of bulbs. The cages last on average about 3-5 years, depending on how moist the soil is, which is about the time that plants/bulbs need dividing and replanting. (Gloves are a necessity to protect hands from rusty pieces of wire.)

An added bonus is that if you decide to move a plant, the cage keeps the rootball perfectly intact. I move many things (lilies included) in full bud or bloom and they don't miss a beat.

My thoughts on planting lilies in pots is that there may be a problem with drainage (waterlogged in wet weather) or the opposite, that the soil may dry out which will stress the bulbs and possibly result in bud drop.

Oh, one last thing about the cages... I have so many of them buried in the garden that in many areas the gophers have given up trying to navigate their way between them.

Good luck with your lilies,

kms