Abilities and Exertion

GURPS Powers 159:
*out-of-body journeys with abilities that have the Projection modifier, incur the same FP cost as hiking.
*Long-Term Use: Low-intensity but relatively constant ability use costs 1 FP per hour.
Also pg 54:
:This isn’t a limitation; it’s no different from the GM ruling
that someone who tosses fireballs all day gets tired (see Abilities and Exertion, p. 159).
pg 157 under Cosmic:
:The GM should also consider waiving Abilities and Exertion
(p. 159). Of course, demigods might stumble and sweat as much as anyone else in a silly campaign
==quotes==
Kromm per http://forums.sjgames.com/showpost.php?p=75802&postcount=11
:POWERS actually rules that *all* "active" abilities have a long-term FP cost, just like digging, hiking, or lifting, and declare that this is part of what you're in for when you buy an "active" advantage.
This could be useful for the 1 FP/hour for Insubstantiality and riding non-insubstantial vehicles which applied in GURPS Spirits via the Hitch a ride rules.
==Analysis==
Requiring something like a Ready maneuver and HT roll (if defined as a physical advantage) or a concentrate roll and a will roll (if defined as a mental advantage) with a bonus equal to the size level of the new object you are trying to anchor to might make sense as a house rule, to reflect "I'm trying to anchor my inherent movements to a car instead of the earth" or vice versa, with failure simply meaning you stay anchored to your previous object (you must always be anchored to something!)
Since Earth has an SM of +43, even someone with an attribute of 0 would always succeed except on a critical failure. Applying Repeated Attempts penalties (if a power) would probably also be fine, since it would take a lot of -1s to actually make a difference for something so large. The FP/attempt would usually be a larger impediment.
As page 6 of GURPS Psionic Powers points out:
:Even passive abilities can be used “actively,” requiring a roll, when getting tricky (pp. 7-11).
or page 8:
:if the task difficulty modifier would be +3 or better, the psi’s effective skill for this feat is at least 15, and it is an unresisted, unopposed action, the GM may wish to allow the ability to work without a roll.
This is similar to No Nuisance Rolls, a perk which would make sense for ghosts who are easily able to attune to a planet and never critically fail at doing so (not usable in combat)
Another basis could be a Power Dodge, since if a ghost is able to transition from "the back support of a bus seat carries me forward, and someone is stabbing a ghost-killing knife at my head" to "the back support of the bus travels right through me and I end up behind the bus" to dodge an attack. Since the HT/Will base is halved here, this reflects how it is harder, and also there wouldn't be any size modifier bonuses. Applying penalties might make sense though. Can a human-sized ghost Hitch a ride on a model airplane?
This is closer to the explanation of how power dodges work with Permeation:
:Only allowed if you’re standing on a surface you can permeate. Success means you sink into the ground and the attack passes over you.
Presumably this works because you allow gravity to affect you, which is optional when standing on an object you can permeate (just as it is for insubstantiality) meaning against an Affects Insubstial attack, a ghost could also simply "fall through the floor" as a form of dodge, though it might just qualify as a normal dodge (like someone flying would do) rather than a power dodge. UNCLEAR
Category:Rules