true story...
Practising winter Ops in the sim a few years ago, simulating slippery conditions, the FO and I decided that we didn't have sufficient grip to provide safe directional control on the ramp and so I set the parkbrake and the FO called up for a tow back onto stand.
The SFI (a First Officer at a "major European Lowcost" as captplaystation would say) was incredulous and enquired "Would you really do that?"
We both said "yes".
He said "well I don't think The Company would be too impressed!"
"They wouldn't be impressed if we skidded off the ramp either" said my colleague on my right, attempting to justify our decision.
4 days later, "The Company" had parked one in the mud at Prestwick.
Draw your own conclusions.