I only do bank wire transfers. Can be difficult during baseball, but I stick to 2500 withdrawals these days, but I will do mulitples if I have to, and can get them for "free". Unless I make a huge future score, which isn't too often.
Obviusly the best way to do it, if you don't need to "collect" the money (for personal use), is book to book transfers which are much more difficult to get. That is if you get low someplace and need to reload see if they will do tarnsfers for you. Makes it more obvious what you are probably doing, but most of the reliable books do not care as long as you are not hitting "winning" sides on them all the time and not reloading.
I am not big on the whole red flag thing anyways. I took a huge chunk out of Canbet and Pinnacle a couple years ago when Fla won the NL pennant, and I took both all at once well into the 5 figures from both. No problems whatsoever. Not from my bank, not from anywhere. And that was two years ago, so I am thinking I am "safe".