Goat format ruling
Royal Command

Card effect (current official text)Flip monsters' effects cannot be activated, also their effects are negated.
Rulings
- This card can be chained to the activation of a Flip Effect from a Flip Summon to negate the Flip Effect. It cannot be activated during the Damage Step, so if a Flip Effect Monster is flipped face-up when attacked you cannot chain Royal Command to negate its Flip Effect.
- If Royal Command is applying on the field both players may still Flip Summon monsters, but any Flip Effects are negated.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Goat forum — sourced change requests get reviewed.