Doubts about forming a crust on a souffle to make it rise further
I think rather than a crust what this process would ideally do is to seal the top a bit so it would trap more steam but still be flexible. The trick is to do it long enough to form that seal but not long enough that it forms an actual crust which would stick to the rim and inhibit rising. A seal forms on the top naturally in the first few minutes in the oven, I think the point of this technique would be to form that seal before baking to prevent steam from escaping before a crust would be formed, maximizing the rise. Whether it would work or not would I am not sure, I would suspect that the souffle ingredients, type of dishes used, and whether the rim is buttered or not would all be factors. The only way to know is to try it both ways and measure the results. If I had to put money on it I'd bet that this technique would get more rise, not by that much though. 

If I was going to try this technique I'd generously butter the rim and side of the souffle dish and carefully monitor the top as it is in the broiler, pulling it out before it forms a real crust. I'd also have a knife or maybe a thin barbecue skewer ready to run around the edge to break off any that has stuck from the side of the rim. 

Now if you want to be really slick, chefy, and slightly geeky you'll use a chef's torch instead to form the seal on the top, that way you can be sure it won't touch the sides and you can control the result completely. 

If you do try this please post the result, I'd be very curious to know how it works for you.