Technically, yes. But you should be cautious when doing so. This is how we usually suggest going about doing it:
For example, say you have a Tone Block 202 and you'd like to run it with your 100 watt cabinet. Plug in and set up the amp to your desired settings. From there, turn up the master and play a bit until you hear the speaker do what we call "bottoming out," which means it's starting to get overpowered. You'll be able to tell by hearing some popping noises.
Pull the master back and make a note to not go past that mark when you play. This way you can play at an appropriate level that won't do damage to your speaker.
While this should work, we would still recommend pairing your amp with a speaker that is matching, or a bit higher in wattage so you don't risk blowing it out. You may have noticed that our cabinets have speakers higher in wattage than the amps they can be paired with. This is essentially why.