Most strange. Here's what I just did. I added a bookmark for checkmyip, and made the bookmark a wifi bookmark. Then I visited the bookmark, got my corporate IP. It was in the BB's cache. Then I hit R to reload, and got my home address!

This tells me that when you hit G in the browser, enter an address, use the menu to switch to the wifi browser, that this is an unreliable method for getting it to do what we want. (By the way, this whole evening, I've had GSM turned off. We're routing BES traffic through wifi.)

Here's the newest question: what are the available methods for forcing a wifi connection? It seems that using a wifi bookmark is the best approach so far. My applications list has "Browser" and "T-Zones" but no "Internet Browser" or "BlackBerry Browser."