Roact components can be mounted and unmounted regularly. Connecting to an event as a statement means you can't disconnect it, creating memory leaks or use after unmount.

Would necessarily be a bit finicky, since it can only check you're calling something with :Connect, and there are likely APIs with their own unrelated Connect method, or weird maids-within-callbacks type deal, but these are likely extremely uncommon and would be worth the author just filtering them out.