You'll be OK. As soon as a RAID0 array goes into degraded mode, it's taken offline. Once both disks are present, it will go back online and things will continue nicely.
However, RAID 0 is very dangerous, so if you do lose all your data, well...
Ok, so if you're running RAID 1, then two things can happen:
Take both disks out at the same time (while the machine is off), and then put them both back at the same time (while it's off)
Take one disk while the machine is off, or, take the disks out one at a time while the system is running
In situation #1, then the machine will just think that the array is no longer present and will skip it (it might also present an error message). When both of the disks are put back, the array will just come back online.
In case #2, the 2nd disk will need to be re-built from the 1st when it is re-inserted because they're no longer in "lock step" (for lack of a better term).
You have a comment stating you want to take them out of RAID. Normally, you can just destroy the array in the controller and the data will live on, but you've said that the array is going to delete your data.
What I would do in that case, is just attach them to some non-RAID ports, or, unplug the disks, delete the array, and then just plug them back in. If it's a cheapo RAID controller (sounds like it is), it will just treat the two disks as normal disks.