Pointless store polices: buying medicine and beer

Pharmacies are apparently not allowed to sell two tubes of hydrocortizone to the same person in the same transaction.

I discovered this at the Milton Tesco a while back and still don't understand the policy. I know it's not possible to buy large quantities of Paracetamol, as they're scared of facilitating suicide. The logic must be that if someone feels suicidal enough to go through the supermarket check out more than once they must really be serious about it whereas those who don't want it so badly will not want to waste the time to queue twice. I wonder how many lives have been saved as a result of this policy?

But Hydrocortizone is a skin cream used to treat eczema. I ran out and wanted to buy a replacement. I thought it sensible to get a tube for home and one for work so I wouldn't have to carry it about with me. Apparently the nanny state thinks I'm not mature enough to make this decision for myself, and selling two tubes to me in one go would tempt me to treat too much eczema in one go? The mind boggles. The lady behind the counter didn't know. I asked her what would stop me buying another one later on and apparently nothing could, unless they happened to recognise me (*).

So why bother?

It was no big deal as I just picked it up the next time I passed a pharmacy, but why inconvenience me because of a rule that isn't possible to enforce? I'm now really intrigued to know how the government thinks I can abuse myself with two tubes of Hydrocortizone instead of one. I've even Google searched for this and can't find anything.

*This reminds me a little of the Sidney St Sainsburys who refused to sell me beer not because I didn't have ID, but because someone else who was with me didn't. Apparently everyone in a group has to have valid ID to prove that they were over 18. This is crazy because there were parents with their kids buying bottles of wine. Why is this any different? I also asked them what would stop me returning to the store without my friend and they said they could only stop me if they noticed me do this. So on my way out of the store I bought the six-pack of Carling and the till on the opposite end, my friend nowhere in sight. I'd like to clarify that we were both well over the age of majority so no law was broken. I raised this with Sainsburys after the event and they told us it was the law, but I have since checked and they are wrong. They have to have a strong belief that the alcohol was being purchased to supply to minors. I'd admit that this was just a minor inconvenience to me (no pun intended), but yet another example of a policy that isn't enforceable and therefore shouldn't be in place. I wonder how many times someone buying alcohol illegally for youths have been thwarted because they were careless enough to bring the youths with them in the check out queue?