Many system in witch magic is subtle and powerful, attain this removing any type of resistance by the "normal" peoples.
This mean that a "non spellcaster" , whatever it's skill, is a sitting duck against magic.
This, to me, is very effective in balancing magic.
Balancing? Making all spells impossible to resist would make the game balanced? Now, that would be a real magic trick!
I have ran games were magic was impossible to resist without charms or other such devices. It worked very well. Best part, a PC could be protected from sleep at lvl 15 rr with one charm and suggestion at level 8rr with another charm. Additionally, certain blanket charms were available, like +15rr versus mental spells, or that convieghed lvl20 rr versus all mental attacks. The charms varied greatly in level or rr or resistance provided, shape and form. Lvl 20 was the highest rr charm I allowed. I used Alchemist General Enchantments to figure out how much skill was required to make a charm (General Enchantment I allowed charms from 1-5th level, General Enchantment II 6th to 10th level, etc). To translate this into a useable skill to make charms, I declared twice the level of the spells were required as ranks in the skill to make the higher level charms. So if generla Enchantment I is level 4, then once a PC had 8 ranks in the Make Charm skill, he could make +5 charms. In time, we stretched out the rule into a table. Basically, at 8 ranks in the skill the N/PC could make +1 charms (i.e. confers a lvl 1rr versus some attack). at 11 ranks +2, etc. This went up to 100 ranks, were +20 could be made. This may seem high, but don't forget that EV skills can gain 4 ranks a level, and OCC skills 6 ranks a level, meaning at level 15-17, the skill could be attained (at level 8-12 if training rules are allowed to gain ranks instead of dev points).
It worked. Magic was feared, but the power of magic never destroyed the game.
BTW, if you opt to use charms, give em some personality. Bound spirits, charms that move or light up when attacked, even charms that shatter after stopping a spell. The charms that break after stopping an attack are great to make as ALWAYS stopping the first appropriate attack and then breaking. I called them spirit charms and they were made by binding a spirit to an object (that was then worn or carried). The spirit was destroyed as it sacrificed itself to stop the attack. This was considered a henious form of the craft. Anyway, LOTS of options on how to deal with rr's.
I always liked the logic of magic being something that could not be resisted without great will or a charm.