Fortunately, the occasion was one in which my actions were legitimate. I was listening to an interesting presentation by a chief superintendent who had brought along samples for inspection by the audience. As he handed them out, we were left in no doubt that he wanted them all back.
When it comes to drugs, I consider myself one of the least street-wise people around. However, even I know that in the quiet suburb where I live, anyone intent on using drugs would not have much trouble finding supplies.
This suggests how pervasive their use has become. The issue extends well beyond urban centres. A secondary headteacher in a rural part of Scotland told me earlier this year that it had reached serious levels in his area.
He recounted, with obvious feeling, the case of a personable and talented former pupil who was now serving his third prison sentence for drugs-related offences.
The chief superintendent explained that youngsters who begin to experiment with drugs are not generally the direct victims of some sinister Mr Big.
They are initiated into risk-taking behaviour by their pals, by siblings, sometimes by adults in their own homes.
They continue through the pub and club scene where drug-taking is an acceptable part of youth culture. A minority become seriously dysfunctional users. Others are able to strike some sort of balance between work, relationships and recreational drug use. Sometimes the difference between the "criminals" and the rest is simply that some get caught.
When it came to the question of rehabilitation, the chief superintendent had no simple solutions. In his experience some addicts respond well to a harsh "cold turkey" regime while others need a more supportive therapeutic environment, with various alternatives in between.
As far as drugs education was concerned, he said that the different agencies need to work in partnership. Many teachers acknowledge that some of their pupils know more about drugs than they do. Familiarity with the latest slang terms (which vary across the country) is an important factor in credibility.
Police officers are not trained teachers but their front-line experience enables them to make a useful contribution. Likewise, voluntary groups, including those working with recovering addicts, have something to offer.
For me, the most disturbing part of the talk concerned the career structure that the drugs trade provides for some young people. Particularly in seriously deprived communities, drugs offer a route to the kind of material rewards that they would find difficult, if not impossible, to achieve by other means.
Where the trade has become well established, there is a hierarchy within the criminal fraternity which enables those who play by the rules to progress through the structure to the point where they can afford two holidays a year in Florida and a BMW.
By contrast, a clutch of Highers and a university place with mounting debts at the end has limited attractions. The chief superintendent argued that the most effective counter-measure is the power to seize the profits of the drugs barons.
That is certainly part of the answer. However, adults also need to engage more honestly with the accusation that they are guilty of hypocrisy and double standards. After all, the most widely abused drug is alcohol.
I think I may give that gin and tonic a miss this evening.
Walter Humes is professor of education and head of educational studies at Strathclyde University.