What might happen if your trip on the Underground is vital

There's a sign on the London Underground that says: 'Dogs must be carried on the escalators'. As an English teacher, I appreciate the humour of the ambiguity. But what if ambiguity isn't your strong point and you take it the wrong way?

I would reckon, if so, that you should WATCH OUT! People might take advantage ...

"Travelcard, please."
"OK, madam. That will be seven pounds exactly. Of course, the dog goes free. [Light-hearted chuckle.]"
"Dog?"
"Yes, dog. Do you have him down there, at your feet?" [Leans over to see.]
"No, that's my new bag. And it's an Armani. Are you trying to be funny?"
"No, Madam. It's just that, with this ticket, you need to have a dog with you. For the escalators. You can't go on them unless you're carrying one."
"But I don't have a dog."
"Well [reassuring no-problem laugh], your train doesn't come for thirty minutes. You have time to pop round to the pet shop. It's just on the High Street. Go down this road, turn left ..."
"I don't WANT to BUY a dog."
"Well, could you just borrow one for a day? They have plenty there. I'm sure they wouldn't miss ...."
"I don't want to BUY a dog, RENT a dog, or even LOOK AT a dog at the moment. I just want to go on the UNDERGROUND."
[Tense pause.]
"Look, I'll do you a deal, Madam. Slip me an extra tenner and you can borrow Rover."
"Who the HELL is Rover?"
[Bends down and retrieves something from under counter.]
"This is Rover, Madam. I can guarantee his good behaviour, he's cheap to feed, and no one will know a thing."
"But - but that's a stuffed aardvark."
"I swear to you, Madam, no one's ever caught on. And if you tuck him well under your arm, bend his nose in a bit, shuffle past the guard really quick, and say 'Come on, Rover, be a good boy and I'll give you a doggy choc', it's a doddle. Done it loads of times meself."
"I'm not sure ..."
"Oh, go on, love. Give it a go. Beat the system! Only a tenner to you. Hey, let's call it seven pound fifty. What about that?"
"I - I don't know -"
"Look, love. What's your alternative? Taking the bus? You don't want to be doing that. People who travel on buses these days ... louts, all of them ... playing their music loud, putting their feet on the seats, eating olives outa jars ..."
"Ugh! You're JOking!"
"See?"
"Okay, then. You've convinced me. The olive thing sounds disgusting. And I guess I have no other choice."
"That's just fourteen pound fifty, then, my dear. And here's Rover for you. [Squeezes aardvark under plastic window. A glass eye pops off in the process.] Whoops. Never mind. A bit of pity for the old dog won't go amiss. So, then, I'll take him back from you tonight on your return. You can let me know how you get on."
"[Customer hands over money. Takes disabled aardvark.] Thank you. You've been so kind. I don't know what I'd have done without you. No, no, keep the change from the twenty."
"That's very sweet of you, Madam. Now, look after Rover, won't you? Keep him under control, ho ho!"
"I will. Thank you. Thank you."
"And don't forget. Just bend his nose over a bit. No one will have a clue. Keep the bad eye on show."
"Yes, thank you. I won't forget."
"See you, then. Have a good journey."
"Thank you."
[Ticket man turns to colleague.] "So, how much have we made, Ernie?"
[Voice from back of ticket office says, 'Three hundred and sixty quid, pal.']
"Quick, here comes another one. Get me another stuffed toy out of the bag."
[Ernie: 'I've only got a rooster and a wild boar left, mate']
"Chuck me the rooster. I didn't do Drama at school for nuffink."
[Raucous laughter from both men.]
New Customer: "Travelcard, please."