The instant invention is designed to detect when undue tension is placed on a belt or strap that is connected to a restraining vest, such undue pressure being indicative that a patient may be in trouble. It is preferable that, whatever sensor is used, it should be elastically resilient to return to its unstressed state after tension on the strap is removed. Additionally, it is preferable that the amount of force that is required in order to trigger an alarm be adjustable to accommodate patients of different weights. Finally, it is also preferable that the level of stress on the strap--and the duration over which it is applied--that is necessary to trigger an alarm be such that the patient cannot easily intentionally cause the device to sound an alarm.