There are some interesting side effects of high powered mages and alternate_spell_power_mechanisms.

Any characters with Magery >= 10, automatically know the detect_magic spell.

Whenever their CURRENT MP is above 30 points, they are automatically detected by anyone else who also knows Detect Magic. In other words, high powered mages can sense each other's presence without even trying. If the daily allotment of MP points is partially spent, and the CURRENT MP drops below 30, the mage is no longer detected AUTOMATICALLY, but still may be detected by an intentional spell.

Aside from other mages, they will also automatically detect the presence of Vida Wood and Power Stones.

This effect may be blocked using Hide_Object with a few slightly altered effects: Range is 3 meters and may cover up to three characters and their gear, but duration is limited to one day. If the character(s) posses any alternate spell powering items, these are also covered.