According to rule <SG1> At the beginning of each match, each alliance robot must be placed such that they are touching
one of the colored alliance tiles and not touching any cube other than those permitted by <SG2>.
Does this mean you can place your robot in the gray tile as long as part of your robot is touching the alliance colored tiles?
For example, place your robot closer to the high goal as long as part of it is touching the alliance tile.
The rule is exactly as you have described it. As long as your robot placement meets the requirements outlined in the rule, the robot placement is legal:
*]Touching the colored tile.
*]Not touching a cube.
Note the robot must also meet the requirements on robot starting configuration (it must start within the 18" x 18" x 18" cube).
The scenario you described (sitting on a grey tile, touching the colored tile) fulfills all the requirements outlined in the rules, and would be legal.