Not necessarily true.
Actually, I had my stock cans on when I drug the brake lever. The can never touched. Looking at pics, it did get close, but never did.Those peg feelers are there for a reason:- the stock cans and sidestand deck out!
If you have aftermarket cans that are thinner or high level, then yes, remove the peg feelers as they touch down very early. If you have standard pipes on your 51 then leave the feelers alone or you risk lifting the rear wheel off the floor as the can decks out and go into a lowside...
Get some aftermarket pipes then off with the feelers!! :twocents
I left mine on for my first track day because I wasn't thinking enough to take them off. Sure as shit they rubbed, then I took them off and scraped peg. Luckily they were the stock pegs so they just folded up or I might have been in worse shape.+1
And in the worst case, the feeler will rip the entire footpeg off the bike.
This happened to a friend of mine, he almost crashed his bike...