就程序法而論，不可能透過「證明」他人未來有犯罪的危險性而將其拘禁，只可能是來自對其意圖與傾向評估後的可接受確定程度。若將刑罰或其他拘束自由的強制措施的發動基礎置於對未來的猜測，而非過去已發生的行為，不僅漠視個體選擇是否從事社會損害行為時的意志能力，因在程序法上難以操作「超越合理懷疑的有罪確信」下，勢須降低對證明程度的要求；標準下調的結果，錯誤風險自然同時升高，何況檢察官對個體的判斷始終存在選擇性起訴的危險。我國規定的九種預防性羈押類型，不僅欠缺情況急迫或情節重大的限制，透過介入時點與其後的剝奪自由效果，形同透過程序法實質的改變了原本不罰預備犯的實體法決定，遑論以「前案科刑執行紀錄」的品格證據作為其「未來」犯罪動機與意圖的臆測憑據，根本違反無罪推定原則。

With regard to procedural law, since it is impossible to ＂prove＂ that a person must be detained because of risk of committing a crime in the future, it is only possible to accept a degree of confidence after assessing the person's intentions and tendencies. If implementation of compulsory measures such as criminal penalties or other restrictions of freedom are based on surmises concerning the future, and not on actual past behavior, this not only ignores individuals' ability to choose not to engage in behavior harmful to society, but would also make it necessary to lower the required degree of proof in order to meet the condition of ＂confidence in guilt beyond reasonable doubt.＂ The risk of error will naturally rise as the standard of proof is lowered, and this is especially the case when a prosecutor may make a selective prosecution of an individual. Not only do the nine types of preventive detention that are permissible in Taiwan lack any restrictions on urgent situations or aggravated circumstances, but also allow the use of procedural law to substantively change judgments concerning inherently illegal preparatory crimes made via substantive law. This is especially true in the case when evidence concerning a person's character made on the basis of the ＂record of implemented punishment for a prior offense＂ is used as a basis for assumption of that person's ＂future＂ criminal motivation and intention, which violates the principle of presumption of innocence.