The presence or absence of liability may hang on a foreseeability test. The fact that the consumption of alcohol or the ingestion of drugs may cause a loss of control is well known. Thus, anyone who knowingly consumes is, at the very least, reckless as to the possibility of losing control. If they did not wish to lose control, they would not consume, so loss of control must be within the scope of their intention by continuing to consume. But, loss of control is not instantaneous and without symptoms. The issue of involuntary consumption is therefore contentious. In most legal systems, involuntary loss of control is limited to cases where there is no real loss of control with noticeable symptoms. Thus, for example, in many states, the blood alcohol level for the commission of the offence of driving under the influence is set sufficiently low that people might exceed the limit without realising that they had consumed enough alcohol to do so. Leaving aside the issue that, in some states, this is a strict liability offense excluding drunkenness as a defense, there is usually a requirement that the person who "spiked" the drinks be prosecuted in place of the driver. This reflects the fact that the commission of a crime has been procured by the actions of secretly adding the alcohol and the practical fact that without this rule, too many accused who are only marginally over the limit, might be encouraged to blame others for their intoxication.