Detecting magical sensors with perception

[Montis]

Core Rulebook p.210 wrote:

Scrying: A scrying spell creates an invisible magical sensor that sends you information.

[...]
A creature can notice the sensor by making a Perception check with a DC 20 + the spell level.

(emphasis mine)

Really? I'd imagine an invisible sensor as really small (tiny or even diminutive) and stationary (invis + stationary = +40 stealth). From that alone the DC should be at least 48 (tiny) or 56 (diminutive).

Or not?

[Some call me Tim]

Montis wrote:

Or not?

It's that damn tiny red light that comes on that gives it away.

[Dolanar]

or that blasted low battery beep perhaps?

[Slaunyeh]

Montis wrote:

Core Rulebook p.210 wrote:

Scrying: A scrying spell creates an invisible magical sensor that sends you information.

[...]
A creature can notice the sensor by making a Perception check with a DC 20 + the spell level.

(emphasis mine)

Really? I'd imagine an invisible sensor as really small (tiny or even diminutive) and stationary (invis + stationary = +40 stealth). From that alone the DC should be at least 48 (tiny) or 56 (diminutive).

Or not?

Yeah. I've always felt it was kinda weird. A tiny invisible sensor should be harder than DC 23 to spot. It's invisible! The way we rule it in our group, is that the DC 20 + spell level is only if you could actually see it. Ie. have some way to detect invisibility.

[Montis]

Okay I guess everyone else agrees with me that this should be handled differently from the RAW.