There's been some confusion regarding locked loadouts in Destiny 2, as gameplay lead Justin Truman's comments to PCGamesN at Gamescom seemed to indicate that these would indeed be locked in some activities:
"When the activity starts, your loadouts are restricted for the duration of that activity," he said. "An example is the Nightfall Strikes, where we wanna make it really about the tactical decision-making of: 'what do I want to bring in to maximise my ability to play this strike with these modifiers on.' You have to make those decisions up front, because we then lock your ability to change your loadout for the duration."
However, this has since been clarified, as Activision responded by saying that these locked loadouts will apply to Nightfall Strikes, but not Raids. Game director Luke Smith also cleared this up on Twitter, saying: "Raids in D2 don't have locked loadouts. We don't want this; "I just got Midnight Coup to drop, let me quit to equip and I'll rejoin.""
Were you worried about locked loadouts on Raids?