Tel them about one. Then show them how it feeds, how it webs up its enclosure and eventually how it molts and the difference in size and colors afterwards.
I did that with my mom. She was heavily opposed to the idea of SEVEN huge spiders in her house. But after showing her how interesting they are, she now often comes and takes a peek at how I feed all twenty five of them.
My neighbor's mom liked Ts so much, she has now got her own H. Incei.
Ts:
0.2.0 B. Vagans (13cm)
1.0.0 L. Parahybana (16cm)
0.1.0 N. Chromatus (13cm)
1.0.0 A. Versicolor (11cm MM)
1.0.0 P. Faciata (17cm)
1.0.0 P. Regalis (16cm MM)
1.0.0 B. Boehmei (4cm)
0.0.1 B. Albopilosum (6cm)
0.0.1 B. Smithi (4cm)
0.0.1 B. Auratum (4cm)
0.0.1 P. Irminia (6cm)
0.0.1 A....