This "probability" is the main problem, along with the wide differences in what casinos label as "fraud", with some screaming "fraud" just because you bet big and had a lucky run when using a large bonus.
It doesn't look fair to confiscate a deposit on the grounds of fraud when the "fraud" was nothing more than aggressive betting of large chunks of the initial bankroll and getting far enough ahead to make the WR and still be in profit.
Sending confiscated deposits to charity would be better than keeping the money for themselves, as often seems the case, but in REAL fraud, those deposits themselves may be from an illegitimate funding source, and the casino confiscating them could lead to someone other than the fraudster suffering.
Although players accused outright of serious fraud are seldom cleared after review, the same cannot be said in those cases of "innocent mistakes" or blunders and misunderstandings by risk departments when verifying players from different countries with their own internal systems of ID validation.
How often do players from the UK and Canada hit the brick wall of being required to send in their "National ID card", and then face an uphill struggle explaining that such a document does not exist in these countries, and that other documents are used instead, many of which are not acceptable substitutes to the casinos, yet are under local guidelines. This leads to confiscated winnings purely on the grounds that the "fraud" is being too ill to be allowed to hold a driving license, and the casino not accepting the standard UK substitute documents that underly the production of a photo document such as a driving license.
If there was more transparency, like we have when fraud is prosecuted in a criminal court, players would be more understanding when casinos claim they are taking the moral high ground in confiscating deposits for the greater good of the innocent customers.
In the case of the man convicted of "bonus abuse"

in a criminal court, it became clear just how BIG a fraud a single player can be, with his case revealing several thousand identities at his disposal for multi accounting.
To find out how they got caught, fraudsters merely need to closely examine the court documents after such a case has been tried, no need therefore to badger casino reps for information as to how they got caught this time so that next time they can do better.
The lack of transparency also means we don't have a picture of the scale of genuine player fraud, which from the forum seems more about "advantage play" and exploiting loopholes, nothing that most big companies would not be happy doing to the detriment of their customers. I think it is hypocracy for casinos to cry foul over advantage players exploiting the loopholes when casinos themselves exploit plenty of loopholes in their efforts to sweat a few more dollars (or Euros/Pounds) from every player. The most obvious "sweating" is the sheer scale of the BS over why payments that used to take 24 hours to process now take 48 or 72, and that even electronic transfers take "a minimum of 3 working days".
If casinos cut the BS and REALLY did their best in terms of fast payments etc, maybe players would be more understanding of the problems they face fighting the fraudsters when occasionally an innocent player is asked for extra documents to clarify something on their account.