Landslide said:
If it really pees you off (as I suspect it would me), why not give audax a go?
In a sportive, you are guided round the route by signs until you come to a junction where someone has stolen or redirected a sign and then you get lost.
In an audax, you are guided round the route by another rider who you think is correctly following a route sheet, until (s)he makes a mistake and then you both get lost. Tradition has it that you are then responsible for improvising a 10 km detour to get back on the correct route. The other rider will follow you until you in turn make a mistake. Route-finding duties alternate until you somehow turn up at event HQ 15 minutes after the last piece of cake has been eaten.
I signed up for
A Mere 200 and discovered that there are more lanes in Cheshire than there are people, so I treated myself to a Garmin Etrex GPS to navigate by - problem solved.
Before I tackle any sportive or audax ride now, I plot the route and upload it to my Etrex. The only times that I've gone off course using the GPS are when I've been chatting to another rider and not looked at the screen in time. It's only been a few hundred metres at worst, and it is very easy to go back for the missed turn.