The trend is in a continuous decline, but it will still keep spiking up during the drop, blowing up leverage, and then going down again... this is part of the tactics of some altcoins. Of course, there are also overall continuous declines where shorting is safe all the way, rather than just spiking up; and there are times when it's safe 99.9% of the time, but suddenly at some moment it skyrockets several times, blowing up shorts... and sometimes even up to 10 times... So, why do I not recommend shorting while also shorting altcoins? You're gambling with your life.