ignore it for the rest of the week/month/season without significant risk of getting stranded?
Well, you can't actually get stranded for this issue. If the solenoid makes a nice loud clunk, then that means the plunger is moving aft and injecting the pinion into the ring gear. Your problem is with the quality of the connection at the inside back of the solenoid cap.
If you are brave, you can take a piece of very stout wire or metal rod or tool in your hand. Hit and hold the starter button so that the plunger stays injected, and then short the two huge terminals on the back of the solenoid. That will get the starter spinning. This is going to make HUGE sparks, and melt some metal and maybe burn your fingers, but the Guzzi will start and you won't be stranded.
Man, I'm just full of good ideas! If you're on a trip, keep putting up with the bad connection until you get home. If you're home, prepare to strip the solenoid.