Consider the following scenario:
You read on Facebook that your ex-partner attended a party the night before he/she is due to have the children for the weekend. You know that they have, in the past, sometimes consumed alcohol to excess. When you were still living together you often had to be the designated driver, if the two of you went to a party. To your knowledge, your ex-partner, has not, previously been charged with any drink driving offence. However, now that the two of you are separated, you are concerned that, without your presence as designated driver, they may be driving whilst under the influence of alcohol. He/she turns up to collect the children. You think he/she might be hungover, but have nothing further that supports this suspicion. They deny this.
Your reasonable response to this situation would be…