Yes, BSD may have used this partition type before Thinkpads (although Thinkpads have had this kind of suspend feature for a long, long time). But messing around with its BIOS and suspend feature would be a major risk for IBM; I can understand that they don't want to do that. In such cases, realistically, open source software is what can and probably should adapt.

Maybe BSD could define an alternative partition type for its standard file system, something that can be used on Thinkpads.