Please use four 15p coins

Two examples of confusing signage brought to you by pragmatics and lexical connotations this week. 

First, I was waiting outside a bakery for my lunch, and there was a phone box (I know! a real one!) with a sign saying this: 

Please be prepared to use four coins to pay the initial minimum fee of 60p. 

I was very puzzled as to why you should have to use four coins to pay this, especially as 60p doesn't even divide evenly into four coins (i.e. there's no 15p coin), so you'd be using a mix of 20p and 10p coins. I thought that probably it meant that you could use more than four, as long as you met the basic criterion of at least four, but wondered why this should be how the phone worked. Does it need four to activate some mechanism? 

I'm sure you're well ahead of me and worked out that it meant at most four coins - so you can use 50p and 10p, three 20p coins, whatever you like, but you can't be there putting in twelve five pences or sixty pennies, which makes much more sense. But the wording 'be prepared' primed me to think it was a minimum requirement that you had to meet, rather than a warning not to exceed a limit. 

Next, my own employer tweeted about the coronavirus restrictions a couple of days before they were relaxed a bit in May. The weekend before the rules changed from no meeting inside at all and maximum six outside to six inside and 30 outside, they shared this image: 

Please remember the 'rule of 6' applies outdoors only until Monday.

You can be fined for not following Government guidelines. Learn more at https://t.co/N0pivTe65t pic.twitter.com/ePjsQDarac

— University of Kent (@UniKent) May 15, 2021

It includes this wording: 

Please remember the 'rule of 6' applies outdoors only until Monday.

I knew what the rules were so I wasn't confused this time. But the placement of only is, as so often, confusing. Does this rule apply 'only until Monday'? Well, yes. Does it apply 'outdoors only'? Well, again, yes. Maybe it's doing double duty and meant 'only outdoors and only until Monday'. But either way, this is still a bit weird to me. 

If a rule only applies in Context A, then the implication is that outside of that context, the rule doesn't apply, and no further action is needed. In other words, there is a restriction outdoors, or until Monday, or both, and anywhere else the restriction doesn't apply. If only is meant to mean 'only until Monday', then it reads like some kind of encouragement, like 'Come on, it's only till Monday, we can do this, one more weekend before we can meet more people!'. But if it applies to 'outdoors', the implication is that this is the stronger restriction, when in fact there was at the time no meeting allowed indoors at all. So you have to interpret it as 'you are allowed to meet up with six people outdoors but not indoors', but a 'rule of 6' sounds like a restriction, not an allowance, because it's called a rule. 

I doubt anyone was ever seriously inconvenienced by either of these things and probably no one else even noticed them, but they both made me stop and think.