@Cat_LeFey I feel like consent is very important, in most cases.
If it's just praying for someone, lighting a candle, stuff like that; I feel like that's okay.
But spells can sometime backfire; I wouldn't want someone to be hindered by a spell that didn't work properly or went wrong. If they gave consent or asked for the spell then it's okay because they know the ''risks''.
Also I've read that spells will work way better when the target consents & gives an offering you can use in your spell.