remote starter and key

So if your remote start goes bad...Will the key still work...? As long as everything is wired properly...You should be fine...! There are some no start issues w/ some GM's(passlock 2)...And rare occasions w/ transponders and the vehicle seeing 2 keys at the same time...But this is usually in happens in the install process and not after install is complete...What year,make ,model do you have...? If you add an alarm...you could get into some other problems...(starter kill)!

If your remote start has anti grind on it and the connection between the R/S anti grind relay and the stock wiring fails your car will not start with the key.  Another possibility, although I have never seen it, would be for something inside the brain to short directly to ground and blow the main power fuse to the ignition.  Typically, the R/S fuse blows first, but under a direct short situation it is very possible the main fuse will blow as well.

So, yes, it is possible, but very, very unlikely.

Are you concerned about this because there is a Key in a bypass box mounted somewhere under your dash?