I needed shower soap and band-aids, but as always headed back to SG to check the ammo situation. Nothing interesting wrt my usual stalking interests (9mm, .45, and .223/5.56), but I am breaking in a new Mossberg 930 JM Pro and decided to pick up four boxes of Win AA Heavy Target Load.
When I got to the register, the clerk asked me if I wanted to split my goods into two purchases, sundries then ammo.

I inquired as to why I would want to do that. The response: "We'll, in case there are problems later."

I said sure, and paid for the ammo with my Amex Gold Card.

I thought about this on the way home. Did the clerk think that I maybe couldn't afford the ammo? Why?
I'm a 6'4", 300#, 48 year-old Caucasian male. I'll admit that I wasn't looking my sharpest today: untucked grey pocket T, khaki cargo pants, black NB running shoes, two-day beard. Hey, it's a holiday and this is Wally World.
Thoughts?