Glassware is delicate. And these glasses are small. My fiancee has broken a good 6 or so in the year I've been active on the site. She even bought me a 6 pack of Glencairns as a b-day present as a testament to her awesomeness and also as an acknowledgement of her glass breaking skills.
These glasses break easy.
Last night my cat ran across the table and kicked a BMH 23 / Saz 18 vatting off the table and shattered the glass in the process.
Anyway, here's to future Glencairn shattering. Bare feet watch out!