When touching a Lamp causes the Lamp to start, yet it sits idle until someone touches it (or something with a fair amount of Capacitance which may or may not be "Grounded" touches it), then it's likely to be a Grounding issue.
It may be a few other things - such as incorrect wiring at the Ballast, incorrect Lamp / Ballast matchup, poor terminations at the Lamp Holder(s), or simply a "no-brainer" like incorrect supply Voltage or bad Lamps.

The "Touch To Start" Lamp deal is from the draining of the field which developes around the Lamp prior to a fat Plasma being established (at the time of initial ionization, when the highest Voltage is impressed across the Lamp).
With Rapid Start (Hot Cathode Operation) Ballasts, the Cathodes (at the ends of the Lamp) should be glowing a dull Orange color.
On Instant Start systems, the Lamps just wait for the Field to be reduced, then they kick into gear.

At times, one may feel a snappy, popping burst - similar to an Electro-Static Discharge ("Carpet Shock"), when touching the Lamp, or Metal Reflector. This happens infrequently, but does get your attention when it occurs!

The Grounded Reflector assists in draining the ESD field, which surrounds the Lamp during the Starting sequences.
When "Other Than Grounded Items / Equipment / Beings / Etc." make contact and cause the Lamp(s) to start, they are allowing the field to be reduced enough for what is needed by the Lamp(s) to get themselves in gear.

I know it sounds kind of silly, but it happens.

Mystery now solved [Linked Image]

Scott35

Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!