First of all, 1m is nothing. Just putting that out there. You being concerned over a 1m trade is you complicating things.
Move traded between my own accounts a few mill on the same IP and never had issues. I've done trades where I literally log in for two minutes, get the GP and log out only to log back in and trade someone else later on.
I don't know if it's because I don't bot so I don't have jagex watching my account/IP but I just do my own shit and never had an issue with RWT. I can almost guarantee you I've had a larger volume trade than everyone complaining on this thread and haven't had an issue.
When I trade I just take my item and that's it. I don't talk in game. I don't give the person a random item - why tf would I take 100m from someone and in return give them five potatoes? Please tell me on what world someone would pay 100m for five potatoes...stupid shit like that is one reason why I would suspect someone of RWT.
Mans just a statement, I've had numerous people call me out on RWT and claim to have reported me. I just said ok and kept on doing what I was doing. Jagex doesn't know wtf you're doing but when you look suspicious then they'll investigate.
Just a for your information, when jagex catches you botting, they don't insta ban. I don't know how well know that little fact is but that's what they do. They catch you and watch you for a bit. Now if they're watching, let's say, five separate accounts, they're watching everything these accounts do. Now if all five accounts trade one person all the items they botted, you tell me how that's not suspicious.
Just use some common sense but don't be stupid about it to the point where you're complicating it and look suspicious.