Thanks for the replies!

It sounds like there is some variation in hissing behaviour. We have had Lilith for nearly half a year now, and I’m still learning things. I didn’t get the sense that she would strike, but I had my 8-year-old son with me (he’s the real herpetophile - is that a word? - in our house, and I don’t trust him not to move unexpectedly and elicit a defensive strike. I’ll put her back in her nice, clean enclosure when I can do so alone. I’ll just chalk the hissing up to grumpiness at being disturbed when she didn’t want to be and keep my eyes open for a possible shed.