CapnZapp
Legend
No it is not inevitable."One scout playing solo" doesn't have to mean mean "one scout gets a solo adventure while everyone else does nothing for an hour."
Just all too common.
What would have happened if that scout rolled badly? An exciting combat (or simply the Rogue getting herself killed) or chase scene or game of cat and mouse, is what. It's simply better with a gentleman's agreement nobody sneaks ahead. After all, another way of phrasing "scouting" is "spoiling the adventure content with only me being there to do anything about it". So if the scouts understand they should do modest and quick scouting, taking minimal risks, then it might not become an issue.
The secret with most official D&D adventures (in sharp contrast with many low fantasy games): you don't need to scout, since encounters aren't intended to be unwinnable. Trust you can handle anything the game throws at you. In the rare case where prudency is the wiser choice, this is nearly always clearly telegraphed as such.
However.
All too many players can't resist the "just one more corner" temptation... Scouting is safe - until it isn't. And when the princess has left her jewelry unguarded I'll just sneak up and take it... Newsflash - the adventure isn't about you acting alone. All your job is, is to confirm something like you aren't being set up - there aren't a dozen extra guards waiting in the shadows. Then you return and enjoy the content TOGETHER.
Or they're slow and cautious, becoming agitated if asked to hurry it along ("Don't force me to act rashly, it might get me killed"). The proper response to that is "okay so we'll skip scouting from now on, since you're apparently unable to get it done with minimal waiting for the rest".
Or... or... or...