He'd probably accept it all the same if it meant not talking to Arcee again when she's in a bad mood. So. Like. Always. As for Prowl - there's the instinct not to tell on him, she doesn't want to, and Arcee doesn't do things she doesn't want to. But he could force her hand, she's not afraid to inform Prime of what he'd been doing if it meant stopping Prowl from going further down this-- well, she's not sure. The path he's on doesn't lead anywhere good, Arcee is sure of that much.

"He's gotten worse since you left, Prime."

There. No details - she and Prowl could work that out between themselves. And if it looked like he wouldn't stop she'd do the things she knew how to do: tell Prime and stop him herself. Because this is different than with Bombshell, Arcee knows it is, but the solution to this particular Prowl problem eludes her still.