At the beginning of a tournament when stacks are deep, if people are randomly going all in it's usually because it's a low stakes game where people don't care about the money and are just looking to gamble early and double up or bust. Coming up with a range to call, say a 100bb open shove, is a bit difficult and extremely player dependent at these stakes.
You won't see this much in higher stakes because it's a terrible play no matter what hand you have.
When stacks are much shorter, say less than 15bb, open shoving all in is part of a well rounded strategy. To counter all ins, you have to use all of your info to determine what % of hands they are shoving in certain positions on certain stack sizes. For example, a player is going to open shove a much wider range with 8bb on the button than they will with 15bb from UTG. Once you estimate a player's range, you can find the range of hands you can profitably call with. ICMizer is a good program to use to solve these spots.