This thread is part of a series where I intend to invent a lot of Techniques, to fill out the support for non-combat skills. There's more about my plans and objectives
here.
Follow Closely (Dancing), Hard, Default: Dancing. Prerequisites: Dancing and Stealth; cannot exceed Dancing +4.
This is the ability to move as one with someone else, at very close quarters, without bumping into them or otherwise giving yourself away. It's mostly useful to those with reliable invisibility, enabling them to get through doors accompanying someone who's unaware of them. This requires a success on Follow Closely (which takes vision and encumbrance penalties), and sufficient success on Stealth that you would not be heard. You also need some reliable way of concealing yourself in plain sight such as Invisibility, Invisibility Art, or ultra-tech equipment. Some kinds of doors give penalties, such as small unpowered revolving doors. Having a visible confederate whose presence is accepted gives +3 to Follow Closely, but may require an Acting roll from them to avoid acting suspiciously. Body Language is often usable as a complementary skill to Follow Closely.
This is a technique rather than an optional specialisation simply because Dancing is DX-based. Dancers trying this for the first time will have an unfamiliarity penalty, which depends on the kinds of dancing they're practised in. Learning the technique is normally confined to specialised infiltrators.
I've encountered security doors, such as the ones at the Old Bailey, which make this trick impractical. They're very sturdy vertical transparent plastic cylinders, only big enough for one person (and not a Very Fat one). They have a door on each side. You go in, the door shuts, and the metal detectors, explosive sniffers and so on do their work. You only get let through if they're happy.