Loki was just untrusting enough to wonder what was going to happen if he did try to break through the spells on that keg. But, as Eileen ain't ever done him wrong yet, he let his curiosity hold sway and pulled another barrel up close to the keg, so he could sit as he worked. Biting his lip, he drew his wand and contemplated the job for several moments before testing with a couple standard diagnostic spells used by thieves to detect magic on doorways and safes.
Magic, yes. Spells...non-standard. Hm.
He started with simple spells, never ruling out simplicity masquerading as perceived complexity as the best camouflage. Testing, playing, seeing what got a reaction from the magic, slowly building the strength and complexity of his spells. Not those glamours, then. Perhaps this locking charm? After some time, he managed to pop the lid off the keg only to be disappointed when it turned up empty.
Frowning, he turned to raise an eyebrow at her. An empty keg that couldn't move? There was something more here than he could see.
All right. Sleight of hand and illusion were his specialty. This would just need a bit more prodding. Once again, he started with testing spells and worked his way through detection and illusion dispelling charms, wondering how far he was being led astray from his true objective and, yet, growing more curious the longer he worked.