Was the Magwitch escape botched?

Does anyone else think Pip and Herbert's escape plan for Magwitch was rather poorly handled? Pip had been rowing a boat up and down The Thames for a month so anyone tailing him could guess that would be the escape route. Pip is told by Mr Wopsle that Compeyson was sitting behind him at the theatre, so he knows he being followed. Then Pip is lured down to the limekiln by Orlick, who tells him he knows all about Magwitch. After escaping from him, you'd have thought Pip would want to re-consider the escape plan. Then, once they have been rowing down the river all day and are stopping overnight, the jack at the inn tells them he thinks customs officers have been rowing up and down the river that day. If I'd been them, I'd have thought, "That's it. Change of plan, let's start walking."

I can't see what all the palava was about anyway. Hardly anyone knows what Magwitch looks like. Just get him on a coach to any port and then out of the country. If they were worried about the customs officers at the ports, they could make for a fishing port and bribe someone to drop them off on the continent. They needn't even leave the country. They could just move to another town or city a couple of hundred miles away, such as Manchester or Plymouth. Identity papers must have been easy enough to forge back then, even if they needed any, which I doubt.

I was surprised Compeyson managed to persuade customs and excise to send six men to look for them on the off-chance that Pip & Magwitch would leave by that route on that day. Perhaps Compeyson told them how rich Magwitch was.

Something else I've been wondering about is that Pip spent about a month rowing a boat up and down the Thames so that anyone tailing him would not get suspicious if he suddenly got into a rowing boat on the day of the escape. Well, that's odd thinking anyway. However, the other thing is I thought the Thames was very dirty and smelly back then. It was virtually an open sewer. Who would choose to go rowing up and down a river surrounded by floating turds for a passtime?