I've noticed the touching thing, too. Not with Lara, but with Thomas and Harry. Someone said Arthur might've been wearing a long-sleeved shirt, which is possible. Or Lara could have had gloves on, but the idea that she was reining in her Hunger is more interesting. However, in the same book, Thomas describes how Lara and another vampire got sick after touching a love symbol (Lara even has the scar), so I don't think merely keeping the Hunger in check is viable.
It's two separate things.
We don't know why it's so, but for some reason the love-energy in symbols of love affects the Whites differently. Maybe it radiates from it, while to encounter it in a person they have to dig in while trying to feed or something. But the effects are simply different.
Maybe a person is like a bottle of energy, and sometimes that energy is contact-poisonous. It's still safe as long as it's in the bottle. I wonder if things like that wedding ring could be compared to an item on which somebody has poured the poisonous energy, so it's coated in the dangerous substance and dangerous on contact, while the bottle of poison is safe unless you open it (i.e. try to feed).
But that's my speculation.
As for Thomas, he burns when he touches Justine because... the demon loves her, too? If the Hunger is capable of feeling love (and it understands the emotion enough to know it hurts it), then feeling it would be self-destructive, so it doesn't matter how much control Thomas has over it (and he has a lot, as he was able to feed off his clients without killing them), near Justine, the Hunger goes crazy, like Gollum (love her/hate her).
No.
Thomas the man loves Justine. Thomas the Hunger wants to
devour Justine. It so happens that these two desires are both passionately intense with regard to her.
Thomas' Hunger tries to feed on
every human being that he comes into skin-to-skin contact with. When Thomas and Harry rap knuckles, Thomas' Hunger tries to feed on Harry. If Thomas saved Karrin from falling off a cliff, his Hunger would try to feed on Karrin at the same time as long as their bodies were touching.
But
most of the time it's easy for Thomas to restrain the Hunger, so he can shake hands or save someone in danger or whatever safely. The exception is if he hasn't fed in so long the Hunger is starving, then he becomes deadly dangerous to everyone around him because the Hunger is off the leash.
The other exception is Justine. As much as Thomas the man loves her, Thomas the Hunger thinks she's absolutely delicious. Thomas' Hunger 'loves' Justine in the same way I that I 'love' good spaghetti or a well-cooked steak, or Harry 'loves' Mama Murphy's burgers. Justine just tastes too good to resist and Thomas can't restrain his Hunger near her.
